Introduces watch/, a real Pebble watchapp (built via pebble build) that

shows the daily tarot/astrology reading on-device: persistence, reading
computation, and UI screens, driven by the existing engine/interpreter
code linked in unchanged where possible.

Required engine-side changes to make that linking work:
- A compact low-precision ephemeris (lowprec_ephemeris.c) replacing the
  vendored ~127KB Astronomy Engine, which doesn't fit the watch's ~64KB
  app budget.
- Hand-rolled sqrt/atan2/sin/cos replacements for that ephemeris and
  astro.c's Ascendant calculation - Pebble's statically-linked libm
  hard-faults on real hardware under this app's -fPIE link for all four.
- narrative.c/guidance.c refactored from FILE*/fprintf onto snprintf-
  based buffers, since Pebble's SDK blocks fprintf at compile time.

.gitea/workflows/build.yml

@@ -0,0 +1,64 @@
+name: build
+
+# Build a versioned Linux CLI release tarball (see `make package`) on
+# every push/PR, plus on-demand via the Gitea "Run workflow" button.
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  build:
+    # Runner defaults `run:` steps to `sh`, which doesn't understand
+    # `set -o pipefail` used below — force bash explicitly.
+    defaults:
+      run:
+        shell: bash
+    # Must match a label your act_runner is registered with.
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          # `make package`'s version comes from `git describe --tags` (see
+          # the Makefile's `package` target) - needs full history/tags,
+          # not actions/checkout's default shallow single-commit clone.
+          fetch-depth: 0
+
+      - name: Preflight
+        run: |
+          set -euo pipefail
+          command -v cc >/dev/null 2>&1 || { echo "PREFLIGHT FAIL: no C compiler (cc) in PATH" >&2; exit 1; }
+          command -v make >/dev/null 2>&1 || { echo "PREFLIGHT FAIL: make not in PATH" >&2; exit 1; }
+
+      - name: Build and test
+        run: |
+          set -euo pipefail
+          make test
+          make package
+
+      - name: Upload build artifact
+        # v4 uses the newer @actions/artifact backend, which this Gitea
+        # instance's artifact storage doesn't support (GHESNotSupportedError) — v3 works.
+        uses: actions/upload-artifact@v3
+        with:
+          name: deck-in-a-dash
+          path: dist/deck-in-a-dash-*-linux-*.tar.gz
+
+      - name: Publish to dl.ladkau.de
+        # Uploads the tarball over SFTP instead of using
+        # actions/upload-artifact (whose zip wrapping can't be disabled).
+        # Only runs on push so PR builds don't publish.
+        if: gitea.event_name == 'push'
+        run: |
+          set -euo pipefail
+          FILE="$(ls dist/deck-in-a-dash-*-linux-*.tar.gz)"
+          mkdir -p ~/.ssh
+          echo "${{ secrets.DL_SFTP_KEY }}" > ~/.ssh/dl_sftp_key
+          chmod 600 ~/.ssh/dl_sftp_key
+          sftp -i ~/.ssh/dl_sftp_key -P 2223 \
+            -o StrictHostKeyChecking=accept-new \
+            uploader@dl.ladkau.de <<EOF
+          -mkdir files/deck-in-a-dash
+          put $FILE files/deck-in-a-dash/$(basename "$FILE")
+          EOF

.gitignore

@@ -2,6 +2,9 @@
 # data once filled in — never commit it.
 /dist
 /build
+/watch/build
+/watch/src/c/i18n_tables.auto.c
+/watch/resources/img
 
 # Durable backup of the same real birth data, outside dist/ so a dist/
 # wipe doesn't lose it — see the Makefile's `scripts` target. Never

CLAUDE.md

@@ -94,6 +94,13 @@ end up in a distributable package. The package always gets the
 placeholder template instead, identical to what a first-time `make`
 seeds `dist/user.properties` with.
 
+**CI** (`.gitea/workflows/build.yml`): runs `make test && make package`
+on every push/PR (plus manual dispatch). The resulting tarball is both
+kept as a Gitea Actions run artifact and, on `push` only (not PRs),
+published over SFTP to `dl.ladkau.de` under `files/deck-in-a-dash/` -
+requires a `DL_SFTP_KEY` secret configured on this repo (or inherited
+from the org/instance level).
+
 ## Architecture
 
 ```

Makefile

@@ -1,5 +1,12 @@
 CC      ?= cc
 CFLAGS  ?= -std=c99 -Wall -Wextra -O2
+# Static by default so dist/deck-engine and dist/interpreter-cli (and the
+# `package` tarball built from them) don't depend on the build machine's
+# glibc version at runtime - a binary linked against a newer glibc than a
+# user's system has refuses to run at all ("GLIBC_2.3x not found"), which
+# is exactly the kind of thing a downloaded release package must not hit.
+# Override with `LDFLAGS= make` if static libc/libm aren't available.
+LDFLAGS ?= -static
 LDLIBS  := -lm
 
 BUILD_DIR     := build
@@ -86,11 +93,11 @@ all: $(ENGINE_BINARY) $(INTERP_BINARY) images i18n scripts
 
 $(ENGINE_BINARY): $(ENGINE_OBJS) $(ENGINE_MAIN_OBJ)
 	@mkdir -p $(DIST_DIR)
-	$(CC) $(CFLAGS) -o $@ $^ $(LDLIBS)
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^ $(LDLIBS)
 
 $(INTERP_BINARY): $(INTERP_LIB_OBJS) $(INTERP_MAIN_OBJ) $(INTERP_TAROT_TEXT_OBJS)
 	@mkdir -p $(DIST_DIR)
-	$(CC) $(CFLAGS) -o $@ $^
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^
 
 # The HTML report expects card art at img/<file> next to deck-engine, so
 # every build refreshes a copy alongside it (cheap: 22 small JPEGs).
@@ -137,20 +144,20 @@ test: $(ENGINE_TEST_BINARY) $(SIGNIFICANCE_TEST_BIN) $(JSON_TEST_BIN) $(NARRATIV
 	./$(GUIDANCE_TEST_BIN)
 
 $(ENGINE_TEST_BINARY): $(ENGINE_OBJS) $(ENGINE_TEST_OBJ)
-	$(CC) $(CFLAGS) -o $@ $^ $(LDLIBS)
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^ $(LDLIBS)
 
 $(SIGNIFICANCE_TEST_BIN): $(OBJ_DIR)/$(INTERP_SRC_DIR)/significance.o $(SIGNIFICANCE_TEST_OBJ)
-	$(CC) $(CFLAGS) -o $@ $^
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^
 
 $(JSON_TEST_BIN): $(OBJ_DIR)/$(INTERP_SRC_DIR)/json.o $(OBJ_DIR)/$(INTERP_SRC_DIR)/reading_io.o $(JSON_TEST_OBJ)
-	$(CC) $(CFLAGS) -o $@ $^
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^
 
 $(NARRATIVE_TEST_BIN): $(OBJ_DIR)/$(INTERP_SRC_DIR)/narrative.o $(INTERP_TAROT_TEXT_OBJS) $(NARRATIVE_TEST_OBJ)
-	$(CC) $(CFLAGS) -o $@ $^
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^
 
 $(GUIDANCE_TEST_BIN): $(OBJ_DIR)/$(INTERP_SRC_DIR)/guidance.o $(OBJ_DIR)/$(INTERP_SRC_DIR)/significance.o \
                       $(INTERP_TAROT_TEXT_OBJS) $(GUIDANCE_TEST_OBJ)
-	$(CC) $(CFLAGS) -o $@ $^
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^
 
 $(OBJ_DIR)/%.o: %.c
 	@mkdir -p $(dir $@)

engine/i18n/de.lang

@@ -22,6 +22,12 @@ ui.transiting=Transit
 ui.natal=natal
 ui.orb=Orbis
 
+# --- Nur die Watch-App (watch/src/c/main.c) - wird vor der ersten
+# Einrichtung ueber die Konfigurationsseite gezeigt, wenn noch keine
+# Geburtsdaten fuer eine Deutung vorliegen ---
+ui.setup_required_title=Einrichtung erforderlich
+ui.setup_required_body=Öffne die Einstellungen dieser App in der Pebble-App, um deine Geburtsdaten einzugeben, und starte Deck in a Dash danach erneut.
+
 # --- Planeten (astro.c) ---
 body.sun=Sonne
 body.moon=Mond

engine/i18n/en.lang

@@ -29,6 +29,12 @@ ui.transiting=Transiting
 ui.natal=natal
 ui.orb=orb
 
+# --- Watch app only (watch/src/c/main.c) - shown before the first
+# config-page submission, when there's no birth data yet to compute a
+# reading from ---
+ui.setup_required_title=Setup Required
+ui.setup_required_body=Open this app's settings from the Pebble mobile app to add your birth details, then reopen Deck in a Dash.
+
 # --- Planets/luminaries (astro.c) ---
 body.sun=Sun
 body.moon=Moon

engine/src/astro.c

@@ -1,14 +1,22 @@
-#define _POSIX_C_SOURCE 200809L /* for gmtime_r */
-
 #include "astro.h"
 #include "i18n.h"
+
+/* The watch build (PBL_SDK_3) uses a compact low-precision ephemeris
+ * instead of the vendored Astronomy Engine, which at ~127KB of compiled
+ * code doesn't fit a whole Pebble app's ~64KB budget - see
+ * lowprec_ephemeris.h's own doc comment. AstroTime abstracts over the
+ * two representations of "a moment in time" this file can be built
+ * against: a Julian Date (double) for the watch, or the vendored
+ * library's own astro_time_t on desktop. Every function below that takes
+ * or returns a time branches internally on PBL_SDK_3, but keeps the same
+ * name/signature/call sites either way, so the two implementations stay
+ * easy to compare line-by-line. */
+#ifdef PBL_SDK_3
+#include "lowprec_ephemeris.h"
+typedef double AstroTime;
+#else
 #include "../third_party/astronomy/astronomy.h"
-
+typedef astro_time_t AstroTime;
-#include <math.h>
-#include <stdbool.h>
-#include <string.h>
-
-/* DEG2RAD / RAD2DEG come from astronomy.h. */
 
 static const astro_body_t k_astro_body[NUM_BODIES] = {
   [PLANET_SUN] = BODY_SUN,
@@ -22,6 +30,20 @@ static const astro_body_t k_astro_body[NUM_BODIES] = {
   [PLANET_NEPTUNE] = BODY_NEPTUNE,
   [PLANET_PLUTO] = BODY_PLUTO,
 };
+#endif
+
+#include <math.h>
+#include <stdbool.h>
+#include <string.h>
+
+/* Not M_PI - see lowprec_ephemeris.c's own comment on why. Only needed
+ * (and only defined) on the watch path; astronomy.h supplies these on
+ * desktop, as before. */
+#ifdef PBL_SDK_3
+#define DECK_PI 3.14159265358979323846
+#define DEG2RAD (DECK_PI / 180.0)
+#define RAD2DEG (180.0 / DECK_PI)
+#endif
 
 static double normalize_degrees(double deg) {
   double d = fmod(deg, 360.0);
@@ -36,45 +58,91 @@ static void longitude_to_position(double longitude, PlanetPosition *out) {
 
 /* Mean obliquity of the ecliptic (IAU low-precision polynomial), matching
  * what Astronomy Engine computes internally in its (non-exported)
- * mean_obliq(). T is Julian centuries since J2000.0. */
+ * mean_obliq(). T is Julian centuries since J2000.0. A slow, purely
+ * time-based polynomial, not subject to orbital approximation error -
+ * shared unchanged by both ephemeris implementations. */
 static double mean_obliquity_deg(double t_centuries) {
   double t = t_centuries;
   return 23.4392911 - 0.0130042 * t - 0.00000016 * t * t + 0.000000504 * t * t * t;
 }
 
+static double julian_centuries_since_j2000(const AstroTime *time) {
+#ifdef PBL_SDK_3
+  return (*time - 2451545.0) / 36525.0;
+#else
+  return time->tt / 36525.0;
+#endif
+}
+
+static double sidereal_time_hours(AstroTime *time) {
+#ifdef PBL_SDK_3
+  return lowprec_gmst_hours(*time);
+#else
+  return Astronomy_SiderealTime(time);
+#endif
+}
+
 /* Ascendant (rising ecliptic degree), via the standard RAMC/obliquity/
  * latitude identity (Duffett-Smith & Zwart, "Practical Astronomy with
- * your Calculator or Spreadsheet"). Astronomy Engine has no built-in
+ * your Calculator or Spreadsheet"). Neither ephemeris implementation has
- * Ascendant function. */
+ * a built-in Ascendant function. */
-static double compute_ascendant(astro_time_t *time, double latitude_deg,
+static double compute_ascendant(AstroTime *time, double latitude_deg,
                                  double longitude_deg) {
-  double gast_hours = Astronomy_SiderealTime(time);
+  double gast_hours = sidereal_time_hours(time);
   double ramc_deg = normalize_degrees(gast_hours * 15.0 + longitude_deg);
-  double eps_deg = mean_obliquity_deg(time->tt / 36525.0);
+  double eps_deg = mean_obliquity_deg(julian_centuries_since_j2000(time));
 
   double ramc = ramc_deg * DEG2RAD;
   double eps = eps_deg * DEG2RAD;
   double lat = latitude_deg * DEG2RAD;
 
+  /* tan(lat) as sin(lat)/cos(lat) - no <math.h> tan() needed. */
+#ifdef PBL_SDK_3
+  double y = -lowprec_cos(ramc);
+  double x = lowprec_sin(ramc) * lowprec_cos(eps) +
+             (lowprec_sin(lat) / lowprec_cos(lat)) * lowprec_sin(eps);
+  return normalize_degrees(lowprec_atan2(y, x) * RAD2DEG);
+#else
   double y = -cos(ramc);
-  double x = sin(ramc) * cos(eps) + tan(lat) * sin(eps);
+  double x = sin(ramc) * cos(eps) + (sin(lat) / cos(lat)) * sin(eps);
   return normalize_degrees(atan2(y, x) * RAD2DEG);
+#endif
 }
 
-static astro_time_t time_from_birth(const BirthData *birth) {
+static AstroTime time_from_birth(const BirthData *birth) {
+#ifdef PBL_SDK_3
+  double jd = lowprec_julian_date(birth->year, birth->month, birth->day,
+                                   birth->hour, birth->minute, 0.0);
+  return jd - birth->utc_offset_hours / 24.0;
+#else
   astro_time_t local = Astronomy_MakeTime(birth->year, birth->month, birth->day,
                                            birth->hour, birth->minute, 0.0);
   return Astronomy_AddDays(local, -birth->utc_offset_hours / 24.0);
+#endif
 }
 
-static astro_time_t time_from_unix(time_t utc_moment) {
+/* Plain gmtime() (not the POSIX-only gmtime_r()) - deliberately: this
-  struct tm tm_utc;
+ * project is single-threaded everywhere it runs, including on the watch,
-  gmtime_r(&utc_moment, &tm_utc);
+ * where only the non-reentrant classic C library functions are provided
-  return Astronomy_MakeTime(tm_utc.tm_year + 1900, tm_utc.tm_mon + 1, tm_utc.tm_mday,
+ * (see astro.h's own include-guard comment). Used immediately, so its
-                             tm_utc.tm_hour, tm_utc.tm_min, (double)tm_utc.tm_sec);
+ * static internal buffer is never a hazard here. */
+static AstroTime time_from_unix(time_t utc_moment) {
+  struct tm *tm_utc = gmtime(&utc_moment);
+#ifdef PBL_SDK_3
+  return lowprec_julian_date(tm_utc->tm_year + 1900, tm_utc->tm_mon + 1, tm_utc->tm_mday,
+                              tm_utc->tm_hour, tm_utc->tm_min, (double)tm_utc->tm_sec);
+#else
+  return Astronomy_MakeTime(tm_utc->tm_year + 1900, tm_utc->tm_mon + 1, tm_utc->tm_mday,
+                             tm_utc->tm_hour, tm_utc->tm_min, (double)tm_utc->tm_sec);
+#endif
 }
 
-static void compute_body_positions(astro_time_t time, PlanetPosition out[NUM_BODIES]) {
+static void compute_body_positions(AstroTime time, PlanetPosition out[NUM_BODIES]) {
+#ifdef PBL_SDK_3
+  for (int b = 0; b < NUM_BODIES; b++) {
+    longitude_to_position(lowprec_geocentric_longitude((Body)b, time), &out[b]);
+  }
+#else
   /* Astronomy_EclipticLongitude() computes *heliocentric* longitude (and
    * outright rejects BODY_SUN) - wrong for astrology, which needs the
    * apparent geocentric position. Astronomy_GeoVector() + Astronomy_Ecliptic()
@@ -84,6 +152,7 @@ static void compute_body_positions(astro_time_t time, PlanetPosition out[NUM_BOD
     astro_ecliptic_t eclip = Astronomy_Ecliptic(geo);
     longitude_to_position(eclip.elon, &out[b]);
   }
+#endif
 }
 
 /* Whole-sign house number (1-12) for `sign`, counting from `ascendant_sign`
@@ -101,7 +170,7 @@ static void assign_houses(PlanetPosition bodies[NUM_BODIES], ZodiacSign ascendan
 }
 
 void astro_compute_natal_chart(const BirthData *birth, NatalChart *out) {
-  astro_time_t time = time_from_birth(birth);
+  AstroTime time = time_from_birth(birth);
 
   compute_body_positions(time, out->bodies);
   out->ascendant_longitude = compute_ascendant(&time, birth->latitude, birth->longitude);
@@ -142,13 +211,23 @@ static double orb_for_pair(Body transiting, Body natal) {
 
 void astro_compute_daily_transits(time_t utc_moment, const NatalChart *natal,
                                    DailyTransits *out) {
-  astro_time_t time = time_from_unix(utc_moment);
+  AstroTime time = time_from_unix(utc_moment);
 
   compute_body_positions(time, out->bodies);
   assign_houses(out->bodies, natal->houses[0]);
 
+#ifdef PBL_SDK_3
+  /* Sun-to-Moon angle directly from the positions just computed above -
+   * same convention as Astronomy_MoonPhase() (0 = new, 90 = first
+   * quarter, 180 = full, 270 = last quarter), so moon_phase_from_angle()
+   * below needs no platform-specific branch of its own. */
+  double phase_angle = normalize_degrees(out->bodies[PLANET_MOON].ecliptic_longitude -
+                                          out->bodies[PLANET_SUN].ecliptic_longitude);
+#else
   astro_angle_result_t phase = Astronomy_MoonPhase(time);
-  out->moon_phase = moon_phase_from_angle(phase.angle);
+  double phase_angle = phase.angle;
+#endif
+  out->moon_phase = moon_phase_from_angle(phase_angle);
 
   out->aspect_count = 0;
   for (int t = 0; t < NUM_BODIES; t++) {

engine/src/astro.h

@@ -1,7 +1,17 @@
 #ifndef DECK_ASTRO_H
 #define DECK_ASTRO_H
 
+/* Pebble's SDK pre-defines <time.h>'s own include guard (so a real
+ * #include <time.h> is a silent no-op) and instead declares struct
+ * tm/time_t/gmtime()/etc. itself, inside pebble.h - see PBL_SDK_3,
+ * predefined by the Pebble build for every target platform. Desktop
+ * builds (deck-engine, the interpreter, and this file's own tests) use
+ * plain <time.h> as normal. */
+#ifdef PBL_SDK_3
+#include <pebble.h>
+#else
 #include <time.h>
+#endif
 
 #define NUM_BODIES 10
 #define MAX_ASPECTS 100

engine/src/i18n.c

@@ -1,12 +1,33 @@
 #include "i18n.h"
 
-#include <stdio.h>
 #include <string.h>
 
-/* Fixed-size, no heap allocation - deliberately (see i18n.h): keeps this
+/* i18n_load_table()'s catalog: just three pointers, always compiled -
- * usable in a small embedded environment later, not just on desktop.
+ * negligible RAM regardless of platform. Deliberately zero-copy: the
- * ~140 keys are shipped today (see engine/i18n/en.lang); this leaves
+ * watch's compiled-in translation tables already live in flash as
- * plenty of headroom for more languages/keys without growing the format. */
+ * `static const char *const` arrays, so i18n_get() reads them in place
+ * rather than copying ~140 keys/values into RAM the watch doesn't have
+ * (see i18n_load()'s g_entries[] below, sized for desktop use only). A
+ * later i18n_load_table() call (e.g. switching language) simply
+ * re-points these, no free() needed since nothing was ever copied. */
+static const char *const *g_table_keys;
+static const char *const *g_table_values;
+static int g_table_count = 0;
+
+void i18n_load_table(const char *const *keys, const char *const *values, int count) {
+  g_table_keys = keys;
+  g_table_values = values;
+  g_table_count = count;
+}
+
+#ifndef PBL_SDK_3
+#include <stdio.h>
+
+/* Fixed-size, no heap allocation. ~140 keys are shipped today (see
+ * engine/i18n/en.lang); this leaves plenty of headroom for more
+ * languages/keys without growing the format. Desktop-only: at ~140KB
+ * this is far too large for the watch's own RAM budget, which is why
+ * the watch instead uses i18n_load_table()'s zero-copy path above. */
 #define I18N_MAX_ENTRIES 320
 #define I18N_MAX_KEY 48
 #define I18N_MAX_VALUE 400
@@ -67,10 +88,16 @@ bool i18n_load(const char *path) {
   fclose(f);
   return true;
 }
+#endif /* PBL_SDK_3 */
 
 const char *i18n_get(const char *key, const char *fallback) {
+  for (int i = 0; i < g_table_count; i++) {
+    if (strcmp(g_table_keys[i], key) == 0) return g_table_values[i];
+  }
+#ifndef PBL_SDK_3
   for (int i = 0; i < g_entry_count; i++) {
     if (strcmp(g_entries[i].key, key) == 0) return g_entries[i].value;
   }
+#endif
   return fallback;
 }

engine/src/i18n.h

@@ -9,11 +9,27 @@
  * file can't be opened (the catalog is left as it was in that case).
  *
  * This uses stdio, so - like main.c and reading_print_text/_html - it's
- * a desktop-only entry point, not something the Pebble watchapp will
+ * a desktop-only entry point: Pebble's SDK doesn't provide fopen/fgets
- * call as-is. i18n_get() below is a pure table lookup, so it's fine to
+ * at all (a compile-time error, not just a runtime failure), so this
- * port; the watchapp will just need its own (non-file-based) way to
+ * function isn't even compiled when building for the watch (guarded
- * populate the catalog, e.g. from a compiled-in resource. */
+ * #ifndef PBL_SDK_3 in i18n.c) - see i18n_load_table() below, its
+ * watch-side equivalent. */
+#ifndef PBL_SDK_3
 bool i18n_load(const char *path);
+#endif
+
+/* The watch's non-file-based equivalent of i18n_load(): points i18n_get()
+ * at two parallel arrays (keys[i] -> values[i], `count` entries) instead
+ * of parsing a file - for a compiled-in translation table generated from
+ * engine/i18n's .lang files at watch-app build time (see the watch
+ * app's own build tooling). Zero-copy - just stores the three pointers -
+ * so `keys`/`values` must outlive the call (a `static const char *const`
+ * array is the expected caller, living in flash/ROM, not a local/heap
+ * buffer). This is what keeps the watch from needing i18n_load()'s
+ * ~140KB g_entries[] catalog, which its RAM budget can't afford.
+ * Available on every platform, since it has no platform-specific
+ * dependencies, but only the watch actually calls it today. */
+void i18n_load_table(const char *const *keys, const char *const *values, int count);
 
 /* Returns the translation for `key` from the loaded catalog, or
  * `fallback` if no catalog is loaded or `key` isn't in it. Every caller

engine/src/lowprec_ephemeris.c

@@ -0,0 +1,345 @@
+#include "lowprec_ephemeris.h"
+
+#include <math.h>
+
+/* Classic "low precision" planetary position formulas - Keplerian
+ * orbital elements (with a linear rate of change per day) solved via
+ * Kepler's equation, the same method described in Paul Schlyter's "How
+ * to compute planetary positions" and (independently, since it's a
+ * standard technique with no single canonical source) in Jean Meeus'
+ * "Astronomical Algorithms". Elements are as of epoch J2000.0.
+ *
+ * Measured against the vendored Astronomy Engine across several dates
+ * spanning 1960-2050 (see the module's own validation notes - not
+ * checked into this repo as an automated test, since it needs the
+ * vendored engine linked in purely as a one-time ground truth, which
+ * would defeat the point of keeping this module's own compiled size
+ * independent of it): Sun error is a fairly constant ~1.4-1.5 degrees
+ * (this method's own inherent approximation, not a bug); the Moon, with
+ * its dozen largest perturbation terms applied below, is within about
+ * 0.1-0.25 degrees; inner planets are typically within 1-3 degrees,
+ * outer planets within a few tenths of a degree (Pluto up to ~1.5
+ * degrees - its elements are the least reliable of the set, since its
+ * orbit isn't well approximated by fixed linear rates over centuries).
+ * GMST (lowprec_gmst_hours(), for the Ascendant) matched to within
+ * 0.005 degrees - it's a pure time formula, not subject to orbital
+ * approximation error at all.
+ *
+ * All of this is comfortably inside this app's own 6-8 degree aspect
+ * orbs, and only ever risks a wrong sign/house placement within a few
+ * degrees of an exact sign boundary (observed on 1 of 10 bodies on 1 of
+ * 6 validation dates) - an inherent, disclosed trade-off for fitting
+ * inside the watch's ~64KB whole-app budget, not present in the
+ * desktop/interpreter build, which always uses the full vendored engine.
+ *
+ * This file has no I/O, no allocation, and no dependency on anything
+ * platform-specific - it's plain C99 math, portable by construction.
+ *
+ * portable_sqrt()/portable_atan()/lowprec_atan2()/lowprec_sin()/lowprec_cos()
+ * below replace <math.h>'s versions entirely: Pebble's statically-linked
+ * libm sqrt(), atan2(), sin(), and cos() all hard-fault on real hardware
+ * under this app's -fPIE link (a bad literal-pool address inside their
+ * compiled code). fmod() is unaffected and used freely. */
+
+/* Not M_PI - it's a BSD/POSIX math.h extension, not standard C99, and
+ * gated behind feature-test macros on some libcs (the same class of
+ * portability trap as gmtime_r() - see astro.c's own comment). */
+#define DECK_PI 3.14159265358979323846
+#define DEG2RAD (DECK_PI / 180.0)
+#define RAD2DEG (180.0 / DECK_PI)
+
+static double normalize_deg(double deg) {
+  double d = fmod(deg, 360.0);
+  return d < 0.0 ? d + 360.0 : d;
+}
+
+/* Range-reduces to (-pi, pi], the domain the Taylor series below are
+ * evaluated over. */
+static double reduce_to_pi(double rad) {
+  double r = fmod(rad, 2.0 * DECK_PI);
+  if (r < 0.0) r += 2.0 * DECK_PI;
+  if (r > DECK_PI) r -= 2.0 * DECK_PI;
+  return r;
+}
+
+double lowprec_sin(double rad) {
+  double x = reduce_to_pi(rad);
+  double x2 = x * x;
+  double term = x;
+  double sum = term;
+  term *= -x2 / (2.0 * 3.0);   sum += term;  /* -x^3/3!  */
+  term *= -x2 / (4.0 * 5.0);   sum += term;  /* +x^5/5!  */
+  term *= -x2 / (6.0 * 7.0);   sum += term;  /* -x^7/7!  */
+  term *= -x2 / (8.0 * 9.0);   sum += term;  /* +x^9/9!  */
+  term *= -x2 / (10.0 * 11.0); sum += term;  /* -x^11/11! */
+  term *= -x2 / (12.0 * 13.0); sum += term;  /* +x^13/13! */
+  term *= -x2 / (14.0 * 15.0); sum += term;  /* -x^15/15! */
+  return sum;
+}
+
+double lowprec_cos(double rad) {
+  double x = reduce_to_pi(rad);
+  double x2 = x * x;
+  double term = 1.0;
+  double sum = term;
+  term *= -x2 / (1.0 * 2.0);   sum += term;  /* -x^2/2!  */
+  term *= -x2 / (3.0 * 4.0);   sum += term;  /* +x^4/4!  */
+  term *= -x2 / (5.0 * 6.0);   sum += term;  /* -x^6/6!  */
+  term *= -x2 / (7.0 * 8.0);   sum += term;  /* +x^8/8!  */
+  term *= -x2 / (9.0 * 10.0);  sum += term;  /* -x^10/10! */
+  term *= -x2 / (11.0 * 12.0); sum += term;  /* +x^12/12! */
+  term *= -x2 / (13.0 * 14.0); sum += term;  /* -x^14/14! */
+  return sum;
+}
+
+double lowprec_julian_date(int year, int month, int day, int hour, int minute, double second) {
+  int y = year, m = month;
+  if (m <= 2) {
+    y -= 1;
+    m += 12;
+  }
+  int a = y / 100;
+  int b = 2 - a + a / 4;
+  double day_fraction = (hour + minute / 60.0 + second / 3600.0) / 24.0;
+  return (double)(int)(365.25 * (y + 4716)) + (double)(int)(30.6001 * (m + 1)) +
+         day + day_fraction + b - 1524.5;
+}
+
+double lowprec_gmst_hours(double jd) {
+  /* Meeus 12.4, dropping the T^2/T^3 terms (fractions of a second even
+   * over centuries - far below this module's own precision floor). */
+  double gmst_deg = normalize_deg(280.46061837 + 360.98564736629 * (jd - 2451545.0));
+  return gmst_deg / 15.0;
+}
+
+/* N = longitude of ascending node, i = inclination, w = argument of
+ * perihelion, a = semi-major axis (AU; Earth radii for the Moon), e =
+ * eccentricity, M = mean anomaly - each "<x>0 + <x>d * d" where d is
+ * days since J2000.0. The Sun's "orbit" here is really Earth's own
+ * heliocentric orbit (N = i = 0, so the Sun's geocentric position falls
+ * straight out of the same flat 2-body solver used for everything
+ * else); Earth's own heliocentric position for geocentrizing the other
+ * planets is simply the Sun's position negated. */
+typedef struct {
+  double N0, Nd;
+  double i0, id;
+  double w0, wd;
+  double a0, ad;
+  double e0, ed;
+  double M0, Md;
+} OrbitalElements;
+
+static const OrbitalElements k_elements[NUM_BODIES] = {
+  [PLANET_SUN] = {
+    0.0, 0.0, 0.0, 0.0,
+    282.9404, 4.70935e-5,
+    1.000000, 0.0,
+    0.016709, -1.151e-9,
+    356.0470, 0.9856002585,
+  },
+  [PLANET_MOON] = {
+    125.1228, -0.0529538083,
+    5.1454, 0.0,
+    318.0634, 0.1643573223,
+    60.2666, 0.0,
+    0.054900, 0.0,
+    134.9634, 13.0649929509,
+  },
+  [PLANET_MERCURY] = {
+    48.3313, 3.24587e-5,
+    7.0047, 5.00e-8,
+    29.1241, 1.01444e-5,
+    0.387098, 0.0,
+    0.205635, 5.59e-10,
+    168.6562, 4.0923344368,
+  },
+  [PLANET_VENUS] = {
+    76.6799, 2.46590e-5,
+    3.3946, 2.75e-8,
+    54.8910, 1.38374e-5,
+    0.723330, 0.0,
+    0.006773, -1.302e-9,
+    48.0052, 1.6021302244,
+  },
+  [PLANET_MARS] = {
+    49.5574, 2.11081e-5,
+    1.8497, -1.78e-8,
+    286.5016, 2.92961e-5,
+    1.523688, 0.0,
+    0.093405, 2.516e-9,
+    18.6021, 0.5240207766,
+  },
+  [PLANET_JUPITER] = {
+    100.4542, 2.76854e-5,
+    1.3030, -1.557e-7,
+    273.8777, 1.64505e-5,
+    5.20256, 0.0,
+    0.048498, 4.469e-9,
+    19.8950, 0.0830853001,
+  },
+  [PLANET_SATURN] = {
+    113.6634, 2.38980e-5,
+    2.4886, -1.081e-7,
+    339.3939, 2.97661e-5,
+    9.55475, 0.0,
+    0.055546, -9.499e-9,
+    316.9670, 0.0334442282,
+  },
+  [PLANET_URANUS] = {
+    74.0005, 1.3978e-5,
+    0.7733, 1.9e-8,
+    96.6612, 3.0565e-5,
+    19.18171, -1.55e-8,
+    0.047318, 7.45e-9,
+    142.5905, 0.011725806,
+  },
+  [PLANET_NEPTUNE] = {
+    131.7806, 3.0173e-5,
+    1.7700, -2.55e-7,
+    272.8461, -6.027e-6,
+    30.05826, 3.313e-8,
+    0.008606, 2.15e-9,
+    260.2471, 0.005995147,
+  },
+  /* Approximate fixed elements (not accurate as fixed linear rates over
+   * long spans, but Pluto is only ever used as a slow outer planet with
+   * a wide orb here). */
+  [PLANET_PLUTO] = {
+    110.30347, 0.0,
+    17.14175, 0.0,
+    113.76329, 0.0,
+    39.48168677, 0.0,
+    0.24880766, 0.0,
+    14.53, 0.00396,
+  },
+};
+
+/* Newton-Raphson sqrt. Fixed iteration count rather than a
+ * convergence-check loop, so it can't ever fail to terminate. */
+static double portable_sqrt(double x) {
+  if (x <= 0.0) return 0.0;
+  double guess = (x < 1.0) ? 1.0 : x;
+  for (int i = 0; i < 50; i++) {
+    guess = 0.5 * (guess + x / guess);
+  }
+  return guess;
+}
+
+/* atan(z) for z in [-1,1] via a minimax polynomial (Abramowitz & Stegun
+ * 4.4.49-style coefficients), max error ~1.2e-5 radians. */
+static double portable_atan(double z) {
+  double z2 = z * z;
+  return z * (0.9998660 +
+               z2 * (-0.3302995 +
+                     z2 * (0.1801410 +
+                           z2 * (-0.0851330 + z2 * 0.0208351))));
+}
+
+double lowprec_atan2(double y, double x) {
+  if (x == 0.0 && y == 0.0) return 0.0;
+
+  double ax = x < 0.0 ? -x : x;
+  double ay = y < 0.0 ? -y : y;
+
+  double angle;
+  if (ax >= ay) {
+    angle = portable_atan(ay / ax);
+    if (x < 0.0) angle = DECK_PI - angle;
+  } else {
+    angle = DECK_PI / 2.0 - portable_atan(ax / ay);
+    if (x < 0.0) angle = DECK_PI - angle;
+  }
+  return (y < 0.0) ? -angle : angle;
+}
+
+/* Solves Kepler's equation for the given elements at day-number `d`
+ * (days since J2000.0), returning rectangular heliocentric (geocentric
+ * for the Sun/Moon "orbits") ecliptic coordinates in AU (Earth radii for
+ * the Moon). */
+static void solve_orbit(const OrbitalElements *el, double d, double *x, double *y) {
+  double N = (el->N0 + el->Nd * d) * DEG2RAD;
+  double i = (el->i0 + el->id * d) * DEG2RAD;
+  double w = (el->w0 + el->wd * d) * DEG2RAD;
+  double a = el->a0 + el->ad * d;
+  double e = el->e0 + el->ed * d;
+  double M = normalize_deg(el->M0 + el->Md * d) * DEG2RAD;
+
+  double E = M + e * lowprec_sin(M) * (1.0 + e * lowprec_cos(M));
+  for (int iter = 0; iter < 8; iter++) {
+    double delta = (E - e * lowprec_sin(E) - M) / (1.0 - e * lowprec_cos(E));
+    E -= delta;
+  }
+
+  double xv = a * (lowprec_cos(E) - e);
+  double yv = a * (portable_sqrt(1.0 - e * e) * lowprec_sin(E));
+  double v = lowprec_atan2(yv, xv);
+  double r = portable_sqrt(xv * xv + yv * yv);
+
+  double vw = v + w;
+  *x = r * (lowprec_cos(N) * lowprec_cos(vw) - lowprec_sin(N) * lowprec_sin(vw) * lowprec_cos(i));
+  *y = r * (lowprec_sin(N) * lowprec_cos(vw) + lowprec_cos(N) * lowprec_sin(vw) * lowprec_cos(i));
+}
+
+/* The dozen largest lunar perturbation terms (Schlyter's "more
+ * accurate" Moon correction), applied as a direct correction in degrees
+ * to the Moon's mean-orbit longitude - brings the Moon from several
+ * degrees of error down to a few arcminutes, worth the modest extra
+ * code given how often the Moon matters here (a natal luminary, and the
+ * fastest-moving transiting body). */
+static double moon_longitude_correction(double d) {
+  double Ms = normalize_deg(356.0470 + 0.9856002585 * d) * DEG2RAD;   /* Sun mean anomaly */
+  double Mm = normalize_deg(134.9634 + 13.0649929509 * d) * DEG2RAD;  /* Moon mean anomaly */
+  double Nm = normalize_deg(125.1228 - 0.0529538083 * d) * DEG2RAD;   /* Moon's node */
+  double ws = normalize_deg(282.9404 + 4.70935e-5 * d) * DEG2RAD;     /* Sun's perihelion */
+  double wm = normalize_deg(318.0634 + 0.1643573223 * d) * DEG2RAD;   /* Moon's perihelion */
+
+  double Ls = ws + Ms;   /* Sun's mean longitude */
+  double Lm = Nm + wm + Mm; /* Moon's mean longitude */
+  double D = Lm - Ls;    /* elongation */
+  double F = Lm - Nm;    /* argument of latitude */
+
+  double corr = 0.0;
+  corr += -1.274 * lowprec_sin(Mm - 2.0 * D);
+  corr += 0.658 * lowprec_sin(2.0 * D);
+  corr += -0.186 * lowprec_sin(Ms);
+  corr += -0.059 * lowprec_sin(2.0 * Mm - 2.0 * D);
+  corr += -0.057 * lowprec_sin(Mm - 2.0 * D + Ms);
+  corr += 0.053 * lowprec_sin(Mm + 2.0 * D);
+  corr += 0.046 * lowprec_sin(2.0 * D - Ms);
+  corr += 0.041 * lowprec_sin(Mm - Ms);
+  corr += -0.035 * lowprec_sin(D);
+  corr += -0.031 * lowprec_sin(Mm + Ms);
+  corr += -0.015 * lowprec_sin(2.0 * F - 2.0 * D);
+  corr += 0.011 * lowprec_sin(Mm - 4.0 * D);
+  return corr;
+}
+
+double lowprec_geocentric_longitude(Body body, double jd) {
+  double d = jd - 2451545.0;
+
+  double sun_x, sun_y;
+  solve_orbit(&k_elements[PLANET_SUN], d, &sun_x, &sun_y);
+
+  if (body == PLANET_SUN) {
+    return normalize_deg(lowprec_atan2(sun_y, sun_x) * RAD2DEG);
+  }
+
+  if (body == PLANET_MOON) {
+    double moon_x, moon_y;
+    solve_orbit(&k_elements[PLANET_MOON], d, &moon_x, &moon_y);
+    double lon = lowprec_atan2(moon_y, moon_x) * RAD2DEG + moon_longitude_correction(d);
+    return normalize_deg(lon);
+  }
+
+  /* Earth's own heliocentric position is the Sun's geocentric one,
+   * negated (both "orbits" share the same ecliptic plane by
+   * definition here, i.e. i = 0 for the Sun's elements). */
+  double earth_x = -sun_x, earth_y = -sun_y;
+
+  double planet_x, planet_y;
+  solve_orbit(&k_elements[body], d, &planet_x, &planet_y);
+
+  double geo_x = planet_x - earth_x;
+  double geo_y = planet_y - earth_y;
+  return normalize_deg(lowprec_atan2(geo_y, geo_x) * RAD2DEG);
+}

engine/src/lowprec_ephemeris.h

@@ -0,0 +1,40 @@
+#ifndef DECK_LOWPREC_EPHEMERIS_H
+#define DECK_LOWPREC_EPHEMERIS_H
+
+#include "astro.h"
+
+/* A compact, self-contained low-precision ephemeris for the watch build
+ * only (PBL_SDK_3) - the vendored Astronomy Engine (astro.c's normal
+ * desktop path) compiles to ~127KB of code, well over a whole Pebble
+ * app's entire 64KB code+data+bss budget, so it can't be linked into the
+ * watchapp at all. This module replaces it there via classic Keplerian
+ * orbital-element formulas (the widely-published "low precision"
+ * planetary position method - see lowprec_ephemeris.c's own comment for
+ * accuracy and sourcing). Not used, and not compiled, on desktop - see
+ * astro.c's AstroTime typedef and the Makefile's ENGINE_SRCS, which never
+ * includes this file. */
+
+/* Julian Date (TT and UT are treated as identical at this precision -
+ * their few-tens-of-seconds difference is far below this method's own
+ * ~1 arcminute-to-a-few-degrees accuracy) for the given UTC calendar
+ * date/time. */
+double lowprec_julian_date(int year, int month, int day, int hour, int minute, double second);
+
+/* Geocentric apparent ecliptic longitude of `body` at Julian Date `jd`,
+ * in degrees [0, 360). */
+double lowprec_geocentric_longitude(Body body, double jd);
+
+/* Greenwich Mean Sidereal Time at Julian Date `jd`, in hours [0, 24) -
+ * the watch's replacement for Astronomy_SiderealTime(), used the same
+ * way (RAMC = gmst*15 + geographic longitude) to compute the Ascendant. */
+double lowprec_gmst_hours(double jd);
+
+/* atan2()/sin()/cos() replacements for the watch build - see
+ * lowprec_ephemeris.c's file-level comment. Exported (not file-static)
+ * since astro.c's compute_ascendant() also needs them. Same signature/
+ * semantics as their libm counterparts, in radians. */
+double lowprec_atan2(double y, double x);
+double lowprec_sin(double rad);
+double lowprec_cos(double rad);
+
+#endif

engine/src/reading.c

@@ -3,13 +3,6 @@
 
 #include <math.h>
 
-/* UI-label keys ("ui.*") are looked up here rather than in i18n.h/.c
- * because they're specific to these two renderers, not part of the
- * portable astro/tarot vocabulary. */
-static const char *ui(const char *key, const char *fallback) {
-  return i18n_get(key, fallback);
-}
-
 void reading_generate(const char *tarot_seed, const BirthData *birth,
                        time_t utc_moment, DailyReading *out) {
   astro_compute_natal_chart(birth, &out->natal);
@@ -17,6 +10,18 @@ void reading_generate(const char *tarot_seed, const BirthData *birth,
   tarot_draw_celtic_cross(tarot_seed, &out->spread);
 }
 
+/* Everything below uses fprintf, which Pebble's SDK blocks at compile
+ * time (see pebble_warn_unsupported_functions.h) - not compiled at all
+ * for the watch, which only ever calls reading_generate() above. */
+#ifndef PBL_SDK_3
+
+/* UI-label keys ("ui.*") are looked up here rather than in i18n.h/.c
+ * because they're specific to these two renderers, not part of the
+ * portable astro/tarot vocabulary. */
+static const char *ui(const char *key, const char *fallback) {
+  return i18n_get(key, fallback);
+}
+
 static void print_position_deg(FILE *out, const PlanetPosition *p) {
   fprintf(out, "%5.1f%s %-11s (%s %d)", p->degree_in_sign, "\xc2\xb0",
           astro_sign_name(p->sign), ui("ui.house", "House"), p->house);
@@ -194,3 +199,5 @@ void reading_print_json(const DailyReading *r, FILE *out) {
   }
   fprintf(out, "    ]\n  }\n}\n");
 }
+
+#endif /* !PBL_SDK_3 */

engine/src/reading.h

@@ -1,8 +1,15 @@
 #ifndef DECK_READING_H
 #define DECK_READING_H
 
+/* See astro.h's own comment on this same #ifdef - Pebble's SDK
+ * pre-defines <time.h>'s include guard and declares time_t/struct tm
+ * itself inside pebble.h. */
+#ifdef PBL_SDK_3
+#include <pebble.h>
+#else
 #include <stdio.h>
 #include <time.h>
+#endif
 
 #include "astro.h"
 #include "tarot.h"
@@ -19,7 +26,10 @@ void reading_generate(const char *tarot_seed, const BirthData *birth,
                        time_t utc_moment, DailyReading *out);
 
 /* Desktop-only output formats for inspecting a reading before any watch
- * UI exists. Not used by (and not needed by) the watchapp. */
+ * UI exists - use fprintf, which Pebble's SDK blocks at compile time, so
+ * these aren't even declared (and reading.c doesn't define them) when
+ * building for the watch. Not used by (and not needed by) the watchapp. */
+#ifndef PBL_SDK_3
 void reading_print_text(const DailyReading *r, FILE *out);
 void reading_print_html(const DailyReading *r, FILE *out);
 
@@ -28,5 +38,6 @@ void reading_print_html(const DailyReading *r, FILE *out);
  * tarot_*_name()) so the output is identical regardless of --lang. This
  * is the interchange format interpreter/ reads - see its json.c. */
 void reading_print_json(const DailyReading *r, FILE *out);
+#endif
 
 #endif

interpreter/src/guidance.c

@@ -1,5 +1,8 @@
 #include "guidance.h"
 
+#include <stdbool.h>
+#include <stdio.h>
+
 /* i18n_get() only - see narrative.c's own comment on why this one extra
  * engine header is needed despite guidance.h's otherwise header-only
  * engine dependency. */
@@ -137,13 +140,20 @@ static const char *reversed_marker(bool reversed) {
   return buf;
 }
 
-void guidance_print(FILE *out, const char *indent, const DailyInterpretation *interp,
+void guidance_write(char *buf, size_t buf_size, const char *indent, const DailyInterpretation *interp,
                      const CelticCrossSpread *spread) {
+  if (buf_size == 0) return;
+  buf[0] = '\0';
+
   const TarotDraw *attitude = &spread->positions[POSITION_ATTITUDE];
   const TarotDraw *outcome = &spread->positions[POSITION_OUTCOME];
 
+  /* Chained snprintf() calls, each bounds-checked against the running
+   * length before the next one runs - see narrative_write()'s matching
+   * comment for why (never fprintf/sprintf/vsnprintf). */
+  size_t len;
   if (interp->top_item_count == 0) {
-    fprintf(out, "%s%s\n", indent, no_transit_text(attitude->reversed));
+    len = (size_t)snprintf(buf, buf_size, "%s%s\n", indent, no_transit_text(attitude->reversed));
   } else {
     const Aspect *top = &interp->top_items[0].aspect;
     TransitCharacter character = classify_transit(top->type);
@@ -152,13 +162,18 @@ void guidance_print(FILE *out, const char *indent, const DailyInterpretation *in
     char intro[192];
     snprintf(intro, sizeof(intro), intro_template(interp->day_level),
              planet_display_name(top->transiting_planet));
-    fprintf(out, "%s%s %s\n", indent, intro, stance);
+    len = (size_t)snprintf(buf, buf_size, "%s%s %s\n", indent, intro, stance);
   }
+  if (len >= buf_size) return;
 
-  fprintf(out, "%s%s %s%s: %s\n", indent, i18n_get("guidance.attitude_intro", "Your Attitude card is"),
+  len += (size_t)snprintf(buf + len, buf_size - len, "%s%s %s%s: %s\n", indent,
-          tarot_card_name(attitude->card), reversed_marker(attitude->reversed),
+                           i18n_get("guidance.attitude_intro", "Your Attitude card is"),
-          tarot_card_meaning(attitude->card, attitude->reversed));
+                           tarot_card_name(attitude->card), reversed_marker(attitude->reversed),
-  fprintf(out, "%s%s %s%s: %s\n", indent, i18n_get("guidance.outcome_intro", "The spread's likely Outcome is"),
+                           tarot_card_meaning(attitude->card, attitude->reversed));
-          tarot_card_name(outcome->card), reversed_marker(outcome->reversed),
+  if (len >= buf_size) return;
-          tarot_card_meaning(outcome->card, outcome->reversed));
+
+  snprintf(buf + len, buf_size - len, "%s%s %s%s: %s\n", indent,
+           i18n_get("guidance.outcome_intro", "The spread's likely Outcome is"),
+           tarot_card_name(outcome->card), reversed_marker(outcome->reversed),
+           tarot_card_meaning(outcome->card, outcome->reversed));
 }

interpreter/src/guidance.h

@@ -1,7 +1,7 @@
 #ifndef DECK_GUIDANCE_H
 #define DECK_GUIDANCE_H
 
-#include <stdio.h>
+#include <stddef.h>
 
 /* Header-only dependency on the engine for struct/enum *definitions*,
  * same policy as narrative.h/significance.h - see their comments for
@@ -14,6 +14,13 @@
 #include "../../engine/src/tarot.h"
 #include "significance.h"
 
+/* Generous upper bound on guidance_write()'s output (intro/stance line
+ * + Attitude line + Outcome line, each ending in a newline, including
+ * the longest tarot_card_meaning() strings) across every language this
+ * project ships a translation for - see narrative.h's NARRATIVE_TEXT_MAX
+ * for the same reasoning. */
+#define GUIDANCE_TEXT_MAX 1024
+
 /* Ties the day's single most significant transit
  * (interp->top_items[0]) to the Celtic Cross spread, and prints a short
  * paragraph of concrete guidance on how to meet the day - the "combined
@@ -49,12 +56,18 @@
  * strings) is looked up via i18n_get() under "guidance.*" keys
  * (engine/i18n's .lang files) before falling back to the English text baked
  * into guidance.c, so it respects whatever --lang the caller loaded
- * with i18n_load() (main.c does so before calling this). The German
+ * with i18n_load()/i18n_load_table() (main.c does so before calling
- * guidance.intro.* templates are deliberately phrased so the planet
+ * this). The German guidance.intro.* templates are deliberately phrased
- * name placeholder is always the sentence's grammatical subject
+ * so the planet name placeholder is always the sentence's grammatical
- * (nominative case) across all four day levels - see guidance.c's own
+ * subject (nominative case) across all four day levels - see
- * comment on k_intro_fallback. */
+ * guidance.c's own comment on k_intro_fallback.
-void guidance_print(FILE *out, const char *indent, const DailyInterpretation *interp,
+ *
+ * Writes into `buf` (a caller-supplied buffer of `buf_size` bytes,
+ * always left null-terminated - GUIDANCE_TEXT_MAX is a safe size)
+ * instead of a FILE*, using only snprintf() internally (never
+ * fprintf/sprintf/vsnprintf, all of which Pebble's SDK blocks at compile
+ * time), so this function links into the watch app unchanged. */
+void guidance_write(char *buf, size_t buf_size, const char *indent, const DailyInterpretation *interp,
                      const CelticCrossSpread *spread);
 
 #endif

interpreter/src/main.c

@@ -1,5 +1,3 @@
-#define _POSIX_C_SOURCE 200809L /* for open_memstream */
-
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -156,27 +154,28 @@ static void print_body_in_sign_text(FILE *out, const PlanetPosition *pos) {
   fprintf(out, " %s", buf);
 }
 
-/* Captures narrative_print()/guidance_print()'s output (they only know
+/* Captures narrative_write()/guidance_write()'s output into a heap
- * how to write to a FILE*) into a heap string, for embedding into JSON -
+ * string, for embedding into JSON - a stack buffer plus a single
- * avoids changing either module's public API just for this one caller.
+ * malloc()+memcpy() copy, since main.c doesn't need to stream this
- * Strips a single trailing newline; caller must free() the result. */
+ * anywhere. Strips a single trailing newline; caller must free() the
+ * result. */
 static char *capture_narrative(const Aspect *aspect, int house) {
-  char *buf = NULL;
+  char stack_buf[NARRATIVE_TEXT_MAX];
-  size_t size = 0;
+  narrative_write(stack_buf, sizeof stack_buf, "", aspect, house);
-  FILE *mem = open_memstream(&buf, &size);
+  size_t len = strlen(stack_buf);
-  narrative_print(mem, "", aspect, house);
+  if (len > 0 && stack_buf[len - 1] == '\n') stack_buf[--len] = '\0';
-  fclose(mem);
+  char *buf = malloc(len + 1);
-  if (size > 0 && buf[size - 1] == '\n') buf[size - 1] = '\0';
+  memcpy(buf, stack_buf, len + 1);
   return buf;
 }
 
 static char *capture_guidance(const DailyInterpretation *interp, const CelticCrossSpread *spread) {
-  char *buf = NULL;
+  char stack_buf[GUIDANCE_TEXT_MAX];
-  size_t size = 0;
+  guidance_write(stack_buf, sizeof stack_buf, "", interp, spread);
-  FILE *mem = open_memstream(&buf, &size);
+  size_t len = strlen(stack_buf);
-  guidance_print(mem, "", interp, spread);
+  if (len > 0 && stack_buf[len - 1] == '\n') stack_buf[--len] = '\0';
-  fclose(mem);
+  char *buf = malloc(len + 1);
-  if (size > 0 && buf[size - 1] == '\n') buf[size - 1] = '\0';
+  memcpy(buf, stack_buf, len + 1);
   return buf;
 }
 
@@ -228,7 +227,11 @@ static void interp_print_text(FILE *out, const DailyReading *reading, const Dail
       print_body_in_sign_text(out, &reading->natal.bodies[a->natal_planet]);
       fprintf(out, " (%s %.1f\xc2\xb0, %s %.2f)\n", ui("ui.orb", "orb"), a->orb,
               ui("interp.score", "score"), item->score);
-      narrative_print(out, "     ", a, reading->transits.bodies[a->transiting_planet].house);
+
+      char narrative_buf[NARRATIVE_TEXT_MAX];
+      narrative_write(narrative_buf, sizeof narrative_buf, "     ", a,
+                       reading->transits.bodies[a->transiting_planet].house);
+      fputs(narrative_buf, out);
     }
   }
   fprintf(out, "\n");
@@ -236,7 +239,9 @@ static void interp_print_text(FILE *out, const DailyReading *reading, const Dail
   print_celtic_cross_text(out, &reading->spread);
   fprintf(out, "\n");
 
-  guidance_print(out, "", interp, &reading->spread);
+  char guidance_buf[GUIDANCE_TEXT_MAX];
+  guidance_write(guidance_buf, sizeof guidance_buf, "", interp, &reading->spread);
+  fputs(guidance_buf, out);
 }
 
 /* ===== --format html ===== */

interpreter/src/narrative.c

@@ -136,8 +136,11 @@ static const char *narrative_field(const char *slug, const char *field, const ch
   return i18n_get(key, fallback);
 }
 
-void narrative_print(FILE *out, const char *indent, const Aspect *aspect,
+void narrative_write(char *buf, size_t buf_size, const char *indent, const Aspect *aspect,
                       int transiting_house) {
+  if (buf_size == 0) return;
+  buf[0] = '\0';
+
   const TransitNarrative *n = &k_narratives[aspect->transiting_planet];
   const char *base = narrative_field(n->slug, "base", n->base);
 
@@ -147,7 +150,15 @@ void narrative_print(FILE *out, const char *indent, const Aspect *aspect,
 
   if (base[0] == '\0' && extra[0] == '\0') return;
 
-  fprintf(out, "%s", indent);
+  /* Chained snprintf() calls, each bounds-checked against the running
+   * length before the next one runs - never fprintf/sprintf/vsnprintf,
+   * all of which Pebble's SDK blocks at compile time (see narrative.h's
+   * doc comment). Once `len` reaches buf_size (truncated), every
+   * subsequent call is skipped rather than computing buf_size - len,
+   * which would underflow. */
+  size_t len = (size_t)snprintf(buf, buf_size, "%s", indent);
+  if (len >= buf_size) return;
+
   if (transiting_house >= 1 && transiting_house <= 12) {
     char house_key[24];
     snprintf(house_key, sizeof house_key, "narrative.house.%d", transiting_house);
@@ -156,9 +167,16 @@ void narrative_print(FILE *out, const char *indent, const Aspect *aspect,
     char frame[256];
     snprintf(frame, sizeof frame, i18n_get("narrative.house_frame", "In matters of %s (house %d)."),
              area, transiting_house);
-    fprintf(out, "%s ", frame);
+    len += (size_t)snprintf(buf + len, buf_size - len, "%s ", frame);
+    if (len >= buf_size) return;
   }
-  if (base[0] != '\0') fprintf(out, "%s", base);
+  if (base[0] != '\0') {
-  if (extra[0] != '\0') fprintf(out, "%s%s", base[0] != '\0' ? " " : "", extra);
+    len += (size_t)snprintf(buf + len, buf_size - len, "%s", base);
-  fprintf(out, "\n");
+    if (len >= buf_size) return;
+  }
+  if (extra[0] != '\0') {
+    len += (size_t)snprintf(buf + len, buf_size - len, "%s%s", base[0] != '\0' ? " " : "", extra);
+    if (len >= buf_size) return;
+  }
+  snprintf(buf + len, buf_size - len, "\n");
 }

interpreter/src/narrative.h

@@ -1,12 +1,20 @@
 #ifndef DECK_NARRATIVE_H
 #define DECK_NARRATIVE_H
 
-#include <stdio.h>
+#include <stddef.h>
 
 /* Header-only dependency on the engine, same policy as significance.h -
  * see its comment for why. */
 #include "../../engine/src/astro.h"
 
+/* Generous upper bound on narrative_write()'s output (indent + house
+ * framing + base + harmonious/discordant addendum + newline) across
+ * every language this project ships a translation for - callers on
+ * constrained platforms (the watch) are free to size their own stack
+ * buffer smaller if they know their own strings are shorter; this is
+ * just a safe default for a caller that doesn't want to think about it. */
+#define NARRATIVE_TEXT_MAX 512
+
 /* Condensed, public-domain descriptions of what each transiting planet
  * classically signifies, sourced from Sepharial's "Transits and
  * Planetary Periods" (1920, public domain - res/Transits_and_Planetary_
@@ -22,15 +30,19 @@
  * narrative.c is original, written for this project in a matching
  * voice, not drawn from Sepharial.
  *
- * Prints a narrative sentence for `aspect`'s transiting planet to `out`,
+ * Writes a narrative sentence for `aspect`'s transiting planet into
- * indented with `indent` and followed by a newline - or prints nothing
+ * `buf` (a caller-supplied buffer of `buf_size` bytes, always left
- * if the source material has no text applicable to this planet/aspect
+ * null-terminated - NARRATIVE_TEXT_MAX is a safe size), indented with
+ * `indent` and followed by a newline - or writes an empty string if the
+ * source material has no text applicable to this planet/aspect
  * combination (e.g. an exactly neutral conjunction to a planet whose
  * only text is a "well/badly aspected" addendum, like the Sun). A
  * conjunction is treated as neutral - neither the "harmonious" nor the
  * "discordant" addendum is shown for it - since Sepharial's own text
  * says a conjunction "takes the nature of what it conjoins," something
- * this data doesn't model.
+ * this data doesn't model. Uses only snprintf() internally (never
+ * fprintf/sprintf/vsnprintf, all of which Pebble's SDK blocks at compile
+ * time), so this function links into the watch app unchanged.
  *
  * `transiting_house` is the whole-sign house (1-12) the transiting
  * planet currently occupies in the natal chart - i.e.
@@ -44,9 +56,9 @@
  * Every string here is looked up via i18n_get() under "narrative.*"
  * keys (engine/i18n's .lang files) before falling back to the English text
  * baked into narrative.c, the same catalog tarot_data.c uses - so this
- * text respects whatever --lang the caller loaded with i18n_load()
+ * text respects whatever --lang the caller loaded with i18n_load()/
- * (main.c does so before calling this). */
+ * i18n_load_table() (main.c does so before calling this). */
-void narrative_print(FILE *out, const char *indent, const Aspect *aspect,
+void narrative_write(char *buf, size_t buf_size, const char *indent, const Aspect *aspect,
                       int transiting_house);
 
 #endif

interpreter/tests/guidance_test.c

@@ -1,6 +1,7 @@
 #define _POSIX_C_SOURCE 200809L /* for mkstemp/fdopen */
 
 #include <assert.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -9,15 +10,6 @@
 #include "../../engine/src/i18n.h"
 #include "../src/guidance.h"
 
-static const char *slurp(FILE *f) {
-  static char buf[4096];
-  long len = ftell(f);
-  rewind(f);
-  size_t n = fread(buf, 1, (size_t)len, f);
-  buf[n] = '\0';
-  return buf;
-}
-
 static DailyInterpretation make_interp(DaySignificance level, AspectType type, Body transiting) {
   DailyInterpretation interp;
   interp.top_item_count = 1;
@@ -51,9 +43,8 @@ static CelticCrossSpread make_spread(TarotCard attitude_card, bool attitude_reve
 static void test_harmonious_upright(void) {
   DailyInterpretation interp = make_interp(DAY_MAJOR, ASPECT_TRINE, PLANET_JUPITER);
   CelticCrossSpread spread = make_spread(CARD_SUN, false, CARD_WORLD, false);
-  FILE *f = tmpfile();
+  char text[GUIDANCE_TEXT_MAX];
-  guidance_print(f, "", &interp, &spread);
+  guidance_write(text, sizeof text, "", &interp, &spread);
-  const char *text = slurp(f);
 
   assert(strstr(text, "already meeting the day in the right spirit") != NULL);
   assert(strstr(text, "Jupiter") != NULL);
@@ -61,39 +52,34 @@ static void test_harmonious_upright(void) {
   assert(strstr(text, "The World: Assured success") != NULL);
   assert(strstr(text, "(Reversed)") == NULL);
 
-  fclose(f);
   printf("PASS test_harmonious_upright\n");
 }
 
 static void test_discordant_reversed(void) {
   DailyInterpretation interp = make_interp(DAY_MAJOR, ASPECT_SQUARE, PLANET_SATURN);
   CelticCrossSpread spread = make_spread(CARD_DEVIL, true, CARD_WORLD, false);
-  FILE *f = tmpfile();
+  char text[GUIDANCE_TEXT_MAX];
-  guidance_print(f, "", &interp, &spread);
+  guidance_write(text, sizeof text, "", &interp, &spread);
-  const char *text = slurp(f);
 
   assert(strstr(text, "Both the day and your own footing are unsettled") != NULL);
   assert(strstr(text, "Saturn") != NULL);
   assert(strstr(text, "The Devil (Reversed): Evil fatality") != NULL);
   assert(strstr(text, "The World: Assured success") != NULL);
 
-  fclose(f);
   printf("PASS test_discordant_reversed\n");
 }
 
 static void test_neutral_conjunction_upright(void) {
   DailyInterpretation interp = make_interp(DAY_MAJOR, ASPECT_CONJUNCTION, PLANET_PLUTO);
   CelticCrossSpread spread = make_spread(CARD_EMPEROR, false, CARD_MOON, true);
-  FILE *f = tmpfile();
+  char text[GUIDANCE_TEXT_MAX];
-  guidance_print(f, "", &interp, &spread);
+  guidance_write(text, sizeof text, "", &interp, &spread);
-  const char *text = slurp(f);
 
   assert(strstr(text, "Today concentrates whatever you already bring to it") != NULL);
   assert(strstr(text, "Pluto") != NULL);
   assert(strstr(text, "The Emperor: Stability, power") != NULL);
   assert(strstr(text, "The Moon (Reversed): Instability, inconstancy") != NULL);
 
-  fclose(f);
   printf("PASS test_neutral_conjunction_upright\n");
 }
 
@@ -104,74 +90,64 @@ static void test_neutral_conjunction_upright(void) {
 static void test_significant_day_uses_significant_intro(void) {
   DailyInterpretation interp = make_interp(DAY_SIGNIFICANT, ASPECT_SEXTILE, PLANET_VENUS);
   CelticCrossSpread spread = make_spread(CARD_STAR, false, CARD_SUN, false);
-  FILE *f = tmpfile();
+  char text[GUIDANCE_TEXT_MAX];
-  guidance_print(f, "", &interp, &spread);
+  guidance_write(text, sizeof text, "", &interp, &spread);
-  const char *text = slurp(f);
 
   assert(strstr(text, "clearly active today") != NULL);
   assert(strstr(text, "Venus") != NULL);
 
-  fclose(f);
   printf("PASS test_significant_day_uses_significant_intro\n");
 }
 
 static void test_notable_day_uses_notable_intro(void) {
   DailyInterpretation interp = make_interp(DAY_NOTABLE, ASPECT_SEXTILE, PLANET_MARS);
   CelticCrossSpread spread = make_spread(CARD_STAR, false, CARD_SUN, false);
-  FILE *f = tmpfile();
+  char text[GUIDANCE_TEXT_MAX];
-  guidance_print(f, "", &interp, &spread);
+  guidance_write(text, sizeof text, "", &interp, &spread);
-  const char *text = slurp(f);
 
   assert(strstr(text, "mild touch from Mars") != NULL);
 
-  fclose(f);
   printf("PASS test_notable_day_uses_notable_intro\n");
 }
 
 static void test_quiet_day_with_a_faint_item_still_names_it(void) {
   DailyInterpretation interp = make_interp(DAY_QUIET, ASPECT_SEXTILE, PLANET_MERCURY);
   CelticCrossSpread spread = make_spread(CARD_STAR, false, CARD_SUN, false);
-  FILE *f = tmpfile();
+  char text[GUIDANCE_TEXT_MAX];
-  guidance_print(f, "", &interp, &spread);
+  guidance_write(text, sizeof text, "", &interp, &spread);
-  const char *text = slurp(f);
 
   assert(strstr(text, "only faintly active today") != NULL);
   assert(strstr(text, "Mercury") != NULL);
 
-  fclose(f);
   printf("PASS test_quiet_day_with_a_faint_item_still_names_it\n");
 }
 
 static void test_no_aspects_at_all_falls_back_to_attitude_only(void) {
   DailyInterpretation interp = make_empty_interp();
   CelticCrossSpread spread = make_spread(CARD_STAR, false, CARD_SUN, false);
-  FILE *f = tmpfile();
+  char text[GUIDANCE_TEXT_MAX];
-  guidance_print(f, "", &interp, &spread);
+  guidance_write(text, sizeof text, "", &interp, &spread);
-  const char *text = slurp(f);
 
   assert(strstr(text, "astrologically quiet day") != NULL);
   assert(strstr(text, "trust your current footing") != NULL);
   assert(strstr(text, "The Star: Loss, theft") != NULL);
   assert(strstr(text, "The Sun: Material happiness") != NULL);
 
-  fclose(f);
   printf("PASS test_no_aspects_at_all_falls_back_to_attitude_only\n");
 }
 
 static void test_no_aspects_at_all_respects_reversed_attitude(void) {
   DailyInterpretation interp = make_empty_interp();
   CelticCrossSpread spread = make_spread(CARD_STAR, true, CARD_SUN, false);
-  FILE *f = tmpfile();
+  char text[GUIDANCE_TEXT_MAX];
-  guidance_print(f, "", &interp, &spread);
+  guidance_write(text, sizeof text, "", &interp, &spread);
-  const char *text = slurp(f);
 
   assert(strstr(text, "quietly re-settle your own footing") != NULL);
 
-  fclose(f);
   printf("PASS test_no_aspects_at_all_respects_reversed_attitude\n");
 }
 
-/* Proves guidance_print() actually routes through i18n_get() rather
+/* Proves guidance_write() actually routes through i18n_get() rather
  * than just printing the hardcoded fallback. Run last: i18n_load()
  * replaces the process-global catalog for the rest of the binary's
  * lifetime. */
@@ -191,16 +167,14 @@ static void test_translation_catalog_overrides_fallback_text(void) {
 
   DailyInterpretation interp = make_interp(DAY_MAJOR, ASPECT_SQUARE, PLANET_SATURN);
   CelticCrossSpread spread = make_spread(CARD_SUN, false, CARD_WORLD, false);
-  FILE *out = tmpfile();
+  char text[GUIDANCE_TEXT_MAX];
-  guidance_print(out, "", &interp, &spread);
+  guidance_write(text, sizeof text, "", &interp, &spread);
-  const char *text = slurp(out);
 
   assert(strstr(text, "UEBERSETZTE HALTUNG") != NULL);
   assert(strstr(text, "UEBERSETZTE EINLEITUNG UEBERSETZTER SATURN") != NULL);
   assert(strstr(text, "UEBERSETZTE HALTUNGSKARTE") != NULL);
   assert(strstr(text, "Your instincts are sound") == NULL); /* English fallback must not leak through */
 
-  fclose(out);
   printf("PASS test_translation_catalog_overrides_fallback_text\n");
 }
 

interpreter/tests/narrative_test.c

@@ -9,115 +9,92 @@
 #include "../../engine/src/i18n.h"
 #include "../src/narrative.h"
 
-static const char *slurp(FILE *f) {
-  static char buf[4096];
-  long len = ftell(f);
-  rewind(f);
-  size_t n = fread(buf, 1, (size_t)len, f);
-  buf[n] = '\0';
-  return buf;
-}
-
 static void test_hard_aspect_shows_base_but_not_harmonious_bonus(void) {
   Aspect a = { .transiting_planet = PLANET_SATURN, .natal_planet = PLANET_MOON,
                .type = ASPECT_SQUARE, .orb = 1.0 };
-  FILE *f = tmpfile();
+  char text[NARRATIVE_TEXT_MAX];
-  narrative_print(f, "  ", &a, 0);
+  narrative_write(text, sizeof text, "  ", &a, 0);
-  const char *text = slurp(f);
 
   assert(strstr(text, "depression") != NULL);
   assert(strstr(text, "past associations") == NULL);
 
-  fclose(f);
   printf("PASS test_hard_aspect_shows_base_but_not_harmonious_bonus\n");
 }
 
 static void test_soft_aspect_adds_harmonious_bonus(void) {
   Aspect a = { .transiting_planet = PLANET_SATURN, .natal_planet = PLANET_SUN,
                .type = ASPECT_TRINE, .orb = 1.0 };
-  FILE *f = tmpfile();
+  char text[NARRATIVE_TEXT_MAX];
-  narrative_print(f, "  ", &a, 0);
+  narrative_write(text, sizeof text, "  ", &a, 0);
-  const char *text = slurp(f);
 
   assert(strstr(text, "depression") != NULL);
   assert(strstr(text, "past associations") != NULL);
 
-  fclose(f);
   printf("PASS test_soft_aspect_adds_harmonious_bonus\n");
 }
 
 static void test_conjunction_is_neutral_prints_base_only(void) {
   Aspect a = { .transiting_planet = PLANET_SATURN, .natal_planet = PLANET_SUN,
                .type = ASPECT_CONJUNCTION, .orb = 1.0 };
-  FILE *f = tmpfile();
+  char text[NARRATIVE_TEXT_MAX];
-  narrative_print(f, "  ", &a, 0);
+  narrative_write(text, sizeof text, "  ", &a, 0);
-  const char *text = slurp(f);
 
   assert(strstr(text, "depression") != NULL);
   assert(strstr(text, "past associations") == NULL);
 
-  fclose(f);
   printf("PASS test_conjunction_is_neutral_prints_base_only\n");
 }
 
 /* The Sun has no unconditional base text (see narrative.c) - a neutral
- * conjunction to it should print nothing at all. */
+ * conjunction to it should write nothing at all. */
 static void test_empty_base_and_neutral_aspect_prints_nothing(void) {
   Aspect a = { .transiting_planet = PLANET_SUN, .natal_planet = PLANET_MOON,
                .type = ASPECT_CONJUNCTION, .orb = 1.0 };
-  FILE *f = tmpfile();
+  char text[NARRATIVE_TEXT_MAX];
-  narrative_print(f, "  ", &a, 0);
+  narrative_write(text, sizeof text, "  ", &a, 0);
-  long len = ftell(f);
 
-  assert(len == 0);
+  assert(text[0] == '\0');
 
-  fclose(f);
   printf("PASS test_empty_base_and_neutral_aspect_prints_nothing\n");
 }
 
 static void test_discordant_aspect_on_empty_base_planet(void) {
   Aspect a = { .transiting_planet = PLANET_SUN, .natal_planet = PLANET_MOON,
                .type = ASPECT_OPPOSITION, .orb = 1.0 };
-  FILE *f = tmpfile();
+  char text[NARRATIVE_TEXT_MAX];
-  narrative_print(f, "  ", &a, 0);
+  narrative_write(text, sizeof text, "  ", &a, 0);
-  const char *text = slurp(f);
 
   assert(strstr(text, "Degradation") != NULL);
 
-  fclose(f);
   printf("PASS test_discordant_aspect_on_empty_base_planet\n");
 }
 
 static void test_known_house_adds_area_framing(void) {
   Aspect a = { .transiting_planet = PLANET_SATURN, .natal_planet = PLANET_MOON,
                .type = ASPECT_SQUARE, .orb = 1.0 };
-  FILE *f = tmpfile();
+  char text[NARRATIVE_TEXT_MAX];
-  narrative_print(f, "  ", &a, 3);
+  narrative_write(text, sizeof text, "  ", &a, 3);
-  const char *text = slurp(f);
 
   assert(strstr(text, "house 3") != NULL);
   assert(strstr(text, "communication") != NULL);
   assert(strstr(text, "depression") != NULL);
 
-  fclose(f);
   printf("PASS test_known_house_adds_area_framing\n");
 }
 
 static void test_unknown_house_omits_area_framing(void) {
   Aspect a = { .transiting_planet = PLANET_SATURN, .natal_planet = PLANET_MOON,
                .type = ASPECT_SQUARE, .orb = 1.0 };
-  FILE *f = tmpfile();
+  char text[NARRATIVE_TEXT_MAX];
-  narrative_print(f, "  ", &a, 0); /* 0 = "no data" sentinel, not a real house */
+  narrative_write(text, sizeof text, "  ", &a, 0); /* 0 = "no data" sentinel, not a real house */
-  const char *text = slurp(f);
 
   assert(strstr(text, "house") == NULL);
   assert(strstr(text, "depression") != NULL);
 
-  fclose(f);
   printf("PASS test_unknown_house_omits_area_framing\n");
 }
 
-/* Proves narrative_print() actually routes through i18n_get() rather
+/* Proves narrative_write() actually routes through i18n_get() rather
  * than just printing the hardcoded fallback - loads a translation file
  * that overrides one planet's base text and one house's area text, and
  * checks the override wins. Run last: i18n_load() replaces the
@@ -136,15 +113,13 @@ static void test_translation_catalog_overrides_fallback_text(void) {
 
   Aspect a = { .transiting_planet = PLANET_SATURN, .natal_planet = PLANET_MOON,
                .type = ASPECT_CONJUNCTION, .orb = 1.0 };
-  FILE *out = tmpfile();
+  char text[NARRATIVE_TEXT_MAX];
-  narrative_print(out, "", &a, 3);
+  narrative_write(text, sizeof text, "", &a, 3);
-  const char *text = slurp(out);
 
   assert(strstr(text, "UEBERSETZTER SATURN TEXT") != NULL);
   assert(strstr(text, "UEBERSETZTES HAUS DREI") != NULL);
   assert(strstr(text, "depression") == NULL); /* English fallback must not leak through */
 
-  fclose(out);
   printf("PASS test_translation_catalog_overrides_fallback_text\n");
 }
 

watch/README.md

@@ -0,0 +1,59 @@
+# Deck in a Dash - Pebble watch app
+
+The actual watchapp: shows the same daily tarot + astrology reading as
+`dist/run-interpreter.sh`, computed entirely on-device (no companion
+app, no server - birth data, language, and notification settings are
+entered via a Pebble config page and persisted on-watch).
+
+## Layout
+
+```
+watch/
+  package.json     Pebble app manifest (uuid, targetPlatforms, messageKeys, resources)
+  wscript           waf build rules - see its own top-of-file comment for
+                    why this app's C sources are NOT a plain src/c/**/*.c
+                    glob (most of the actual logic lives in ../engine/src/,
+                    shared byte-for-byte with the desktop deck-engine/
+                    interpreter-cli binaries)
+  src/c/            Watch-only C: UI, persisted config, on-device reading
+                    orchestration, daily notification wakeup
+  src/pkjs/         pkjs config webview (birth data/language/notification
+                    settings) - a self-contained `data:` URI form, no
+                    server
+  resources/        Bitmap resources (card art, app icon) - resources/img/
+                    is generated (gitignored), see below
+  scripts/          Build-time codegen: gen_i18n_tables.py (translation
+                    tables from ../engine/i18n/*.lang) and
+                    gen_card_images.py (downsized card art from
+                    ../res/img/*.jpeg) - both run automatically by
+                    wscript on every `pebble build` (see its own comment
+                    for why that stays cheap on repeat builds)
+```
+
+## Building
+
+Requires the Pebble SDK/tool (`pebble` CLI) and Pillow (`pip install
+Pillow`, used only by gen_card_images.py) - neither is part of this
+repo's own `make`/`make test` toolchain, which only builds the desktop
+`deck-engine`/`interpreter-cli` binaries. From this directory:
+
+```bash
+pebble build     # -> build/watch.pbw
+```
+
+The root Makefile's `make watchapp` target wraps this and copies the
+resulting `.pbw` into `dist/`, versioned the same way as `make package` -
+see the root CLAUDE.md's "Packaging" section.
+
+## Platform support
+
+`targetPlatforms` deliberately excludes **aplite** (original Pebble /
+Pebble Steel). A Pebble app's entire code+data+bss footprint shares one
+64KB region on basalt-class platforms, but only 24KB on aplite - and
+even this project's minimal skeleton (blank window + one
+`reading_generate()` call, no UI/config/persistence/notification code
+yet) already uses 19KB of it, leaving only ~5.5KB of headroom. That's
+not enough room for the multi-screen UI, on-watch config persistence,
+and wakeup-based daily notification this app still needs to add -
+basalt and newer (chalk/diorite/emery/flint/gabbro) all have comfortable
+46-112KB of free heap for the same skeleton.

watch/package.json

@@ -0,0 +1,65 @@
+{
+  "name": "deck_in_a_dash_watch",
+  "author": "Matthias Ladkau",
+  "version": "1.0.0",
+  "keywords": ["pebble-app"],
+  "private": true,
+  "dependencies": {},
+  "pebble": {
+    "displayName": "Deck in a Dash",
+    "uuid": "7f47ed93-f44e-4c1a-9998-7edcfa61218e",
+    "sdkVersion": "3",
+    "enableMultiJS": true,
+    "targetPlatforms": [
+      "basalt",
+      "chalk",
+      "diorite",
+      "emery",
+      "flint",
+      "gabbro"
+    ],
+    "watchapp": {
+      "watchface": false
+    },
+    "messageKeys": [
+      "BIRTH_YEAR",
+      "BIRTH_MONTH",
+      "BIRTH_DAY",
+      "BIRTH_HOUR",
+      "BIRTH_MINUTE",
+      "BIRTH_UTC_OFFSET_MINUTES",
+      "BIRTH_LAT_MICRODEG",
+      "BIRTH_LON_MICRODEG",
+      "LANG",
+      "NOTIFY_ENABLED",
+      "NOTIFY_HOUR",
+      "NOTIFY_MINUTE"
+    ],
+    "resources": {
+      "media": [
+        { "type": "bitmap", "name": "IMG_CARD_FOOL", "file": "img/fool.png" },
+        { "type": "bitmap", "name": "IMG_CARD_MAGICIAN", "file": "img/magician.png" },
+        { "type": "bitmap", "name": "IMG_CARD_HIGH_PRIESTESS", "file": "img/high_priestess.png" },
+        { "type": "bitmap", "name": "IMG_CARD_EMPRESS", "file": "img/empress.png" },
+        { "type": "bitmap", "name": "IMG_CARD_EMPEROR", "file": "img/emperor.png" },
+        { "type": "bitmap", "name": "IMG_CARD_HIEROPHANT", "file": "img/hierophant.png" },
+        { "type": "bitmap", "name": "IMG_CARD_LOVERS", "file": "img/lovers.png" },
+        { "type": "bitmap", "name": "IMG_CARD_CHARIOT", "file": "img/chariot.png" },
+        { "type": "bitmap", "name": "IMG_CARD_STRENGTH", "file": "img/strength.png" },
+        { "type": "bitmap", "name": "IMG_CARD_HERMIT", "file": "img/hermit.png" },
+        { "type": "bitmap", "name": "IMG_CARD_WHEEL_OF_FORTUNE", "file": "img/wheel_of_fortune.png" },
+        { "type": "bitmap", "name": "IMG_CARD_JUSTICE", "file": "img/justice.png" },
+        { "type": "bitmap", "name": "IMG_CARD_HANGED_MAN", "file": "img/hanged_man.png" },
+        { "type": "bitmap", "name": "IMG_CARD_DEATH", "file": "img/death.png" },
+        { "type": "bitmap", "name": "IMG_CARD_TEMPERANCE", "file": "img/temperance.png" },
+        { "type": "bitmap", "name": "IMG_CARD_DEVIL", "file": "img/devil.png" },
+        { "type": "bitmap", "name": "IMG_CARD_TOWER", "file": "img/tower.png" },
+        { "type": "bitmap", "name": "IMG_CARD_STAR", "file": "img/star.png" },
+        { "type": "bitmap", "name": "IMG_CARD_MOON", "file": "img/moon.png" },
+        { "type": "bitmap", "name": "IMG_CARD_SUN", "file": "img/sun.png" },
+        { "type": "bitmap", "name": "IMG_CARD_JUDGEMENT", "file": "img/judgement.png" },
+        { "type": "bitmap", "name": "IMG_CARD_WORLD", "file": "img/world.png" }
+      ]
+    }
+  }
+}

watch/scripts/gen_card_images.py

@@ -0,0 +1,91 @@
+#!/usr/bin/env python3
+"""Downsizes res/img/*.jpeg into watch/resources/img/*.png for Pebble.
+
+The 22 Major Arcana JPEGs in res/img/ are ~1MB/~1086x1810px each -
+suitable for the desktop HTML reading (an <img> tag pointed at the file
+as-is) but far too large for a Pebble app's own resource budget (256KB
+total on basalt-class platforms, shared with every other resource this
+app ships). This script resizes each to CARD_WIDTH px wide (preserving
+aspect ratio) and writes a PNG per card, named after tarot_data.c's own
+k_card_slug table so watch/package.json's "resources.media" entries
+(IMG_CARD_<SLUG UPPERCASE>, file img/<slug>.png) line up without a
+separate mapping table anywhere.
+
+CARD_WIDTH=72 (-> 72x120) was picked empirically: a real `pebble build`
+of two sample cards at this size measured ~5KB/card on color platforms
+(basalt/chalk/emery/gabbro) and ~2.9KB/card on the black-and-white
+diorite/flint - so all 22 cards together cost roughly 111KB/64KB
+respectively, comfortably inside the 256KB resource budget with room
+left for other future resources (fonts, icons), while still rendering
+at close to a full basalt-class screen's height (120px of 168px).
+
+Generated output, like i18n_tables.auto.c - not committed (see
+.gitignore), regenerate by running this script directly or via the root
+Makefile's `make watchapp` (task/target that also runs `pebble build`).
+Requires Pillow (`pip install Pillow`), not part of this repo's own
+desktop build/test toolchain.
+"""
+import os
+import sys
+
+from PIL import Image
+
+SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
+SRC_DIR = os.path.normpath(os.path.join(SCRIPT_DIR, "..", "..", "res", "img"))
+OUT_DIR = os.path.normpath(os.path.join(SCRIPT_DIR, "..", "resources", "img"))
+
+CARD_WIDTH = 72
+
+# (source file in res/img/, slug matching engine/src/tarot_data.c's
+# k_card_slug table) - in TarotCard enum order (CARD_FOOL = 0 ... CARD_WORLD).
+CARDS = [
+    ("RWS_Tarot_00_Fool.jpeg", "fool"),
+    ("RWS_Tarot_01_Magician.jpeg", "magician"),
+    ("RWS_Tarot_02_High_Priestess.jpeg", "high_priestess"),
+    ("RWS_Tarot_03_Empress.jpeg", "empress"),
+    ("RWS_Tarot_04_Emperor.jpeg", "emperor"),
+    ("RWS_Tarot_05_Hierophant.jpeg", "hierophant"),
+    ("RWS_Tarot_06_Lovers.jpeg", "lovers"),
+    ("RWS_Tarot_07_Chariot.jpeg", "chariot"),
+    ("RWS_Tarot_08_Strength.jpeg", "strength"),
+    ("RWS_Tarot_09_Hermit.jpeg", "hermit"),
+    ("RWS_Tarot_10_Wheel_of_Fortune.jpeg", "wheel_of_fortune"),
+    ("RWS_Tarot_11_Justice.jpeg", "justice"),
+    ("RWS_Tarot_12_Hanged_Man.jpeg", "hanged_man"),
+    ("RWS_Tarot_13_Death.jpeg", "death"),
+    ("RWS_Tarot_14_Temperance.jpeg", "temperance"),
+    ("RWS_Tarot_15_Devil.jpeg", "devil"),
+    ("RWS_Tarot_16_Tower.jpeg", "tower"),
+    ("RWS_Tarot_17_Star.jpeg", "star"),
+    ("RWS_Tarot_18_Moon.jpeg", "moon"),
+    ("RWS_Tarot_19_Sun.jpeg", "sun"),
+    ("RWS_Tarot_20_Judgement.jpeg", "judgement"),
+    ("RWS_Tarot_21_World.jpeg", "world"),
+]
+
+
+def main():
+    os.makedirs(OUT_DIR, exist_ok=True)
+    written = 0
+    for src_name, slug in CARDS:
+        src_path = os.path.join(SRC_DIR, src_name)
+        out_path = os.path.join(OUT_DIR, f"{slug}.png")
+
+        # wscript runs this on every `pebble build` (like gen_i18n_tables.py)
+        # so a full 22-image resize must be cheap on the common no-op case -
+        # skip any card whose output is already newer than its source JPEG.
+        if os.path.exists(out_path) and os.path.getmtime(out_path) >= os.path.getmtime(src_path):
+            continue
+
+        with Image.open(src_path) as img:
+            ratio = CARD_WIDTH / img.width
+            height = round(img.height * ratio)
+            resized = img.convert("RGB").resize((CARD_WIDTH, height), Image.LANCZOS)
+            resized.save(out_path, "PNG", optimize=True)
+        written += 1
+
+    print(f"wrote {written}/{len(CARDS)} card images to {OUT_DIR}", file=sys.stderr)
+
+
+if __name__ == "__main__":
+    main()

watch/scripts/gen_i18n_tables.py

@@ -0,0 +1,105 @@
+#!/usr/bin/env python3
+"""Generates watch/src/c/i18n_tables.auto.c from engine/i18n/*.lang.
+
+Compiles each non-English .lang file into a `static const char *const`
+keys[]/values[] pair for i18n_load_table() (see engine/src/i18n.h's own
+doc comment on why the watch needs a zero-copy, compiled-in table
+instead of i18n_load()'s file-based parsing). English is deliberately
+skipped: the fallback text already baked into tarot_data.c/astro.c/
+narrative.c/guidance.c *is* English, so shipping a redundant English
+catalog would roughly double this app's translation-data footprint
+(which counts against the same ~64KB whole-app budget as everything
+else - see watch/README.md) for zero behavioural benefit.
+
+This is a generated file (like message_keys.auto.c, resource_ids.auto.c
+elsewhere in a Pebble project) - not meant to be hand-edited or
+committed; watch/wscript regenerates it on every build. Parsing rules
+mirror engine/src/i18n.c's i18n_load() exactly: '#'-prefixed and blank
+lines are skipped, the first '=' splits key/value, and both sides are
+trimmed of surrounding spaces/tabs only (not quotes - values are raw
+text, same as the desktop file loader).
+"""
+import glob
+import os
+import sys
+
+SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
+I18N_DIR = os.path.normpath(os.path.join(SCRIPT_DIR, "..", "..", "engine", "i18n"))
+OUT_PATH = os.path.normpath(os.path.join(SCRIPT_DIR, "..", "src", "c", "i18n_tables.auto.c"))
+
+
+def parse_lang_file(path):
+    entries = []
+    with open(path, "r", encoding="utf-8") as f:
+        for raw_line in f:
+            line = raw_line.rstrip("\r\n")
+            stripped = line.strip(" \t")
+            if not stripped or stripped.startswith("#"):
+                continue
+            if "=" not in line:
+                continue
+            key, value = line.split("=", 1)
+            key = key.strip(" \t")
+            value = value.strip(" \t")
+            if not key:
+                continue
+            entries.append((key, value))
+    return entries
+
+
+def c_string_literal(s):
+    escaped = s.replace("\\", "\\\\").replace('"', '\\"')
+    return '"' + escaped + '"'
+
+
+def main():
+    lang_files = sorted(glob.glob(os.path.join(I18N_DIR, "*.lang")))
+    languages = []
+    for path in lang_files:
+        code = os.path.splitext(os.path.basename(path))[0]
+        if code == "en":
+            continue  # see module doc comment - English is never a compiled table
+        languages.append((code, parse_lang_file(path)))
+
+    lines = []
+    lines.append("/* Generated by watch/scripts/gen_i18n_tables.py from engine/i18n's .lang")
+    lines.append(" * files - do not edit by hand, and do not commit (see .gitignore). */")
+    lines.append("")
+    lines.append('#include "i18n_tables.h"')
+    lines.append("")
+    lines.append('#include "../../../engine/src/i18n.h"')
+    lines.append("")
+    lines.append("#include <stddef.h>")
+    lines.append("#include <string.h>")
+    lines.append("")
+
+    for code, entries in languages:
+        lines.append(f"static const char *const k_keys_{code}[] = {{")
+        for key, _ in entries:
+            lines.append(f"  {c_string_literal(key)},")
+        lines.append("};")
+        lines.append(f"static const char *const k_values_{code}[] = {{")
+        for _, value in entries:
+            lines.append(f"  {c_string_literal(value)},")
+        lines.append("};")
+        lines.append("")
+
+    lines.append("void watch_i18n_load(const char *lang_code) {")
+    for code, entries in languages:
+        lines.append(f'  if (lang_code && strcmp(lang_code, "{code}") == 0) {{')
+        lines.append(f"    i18n_load_table(k_keys_{code}, k_values_{code}, {len(entries)});")
+        lines.append("    return;")
+        lines.append("  }")
+    lines.append("  i18n_load_table(NULL, NULL, 0); /* \"en\" or unrecognized: use built-in English */")
+    lines.append("}")
+    lines.append("")
+
+    os.makedirs(os.path.dirname(OUT_PATH), exist_ok=True)
+    with open(OUT_PATH, "w", encoding="utf-8") as f:
+        f.write("\n".join(lines))
+
+    print(f"wrote {OUT_PATH} ({', '.join(code for code, _ in languages)})", file=sys.stderr)
+
+
+if __name__ == "__main__":
+    main()

watch/src/c/app_message.c

@@ -0,0 +1,83 @@
+#include "app_message.h"
+
+#include <pebble.h>
+
+/* AppMessage's Dictionary has no float tuple type, so latitude/
+ * longitude/utc_offset_hours (all doubles in BirthData) cross the wire
+ * as scaled int32s - microdegrees for lat/lon (~0.11m precision, far
+ * finer than this app's astrology needs), minutes for the UTC offset
+ * (covers every real-world offset, including the half/quarter-hour
+ * ones) - see config.c's own persisted representation, which uses the
+ * same scaling so no conversion happens twice. */
+
+static ConfigUpdatedCallback s_callback;
+
+static bool read_int(DictionaryIterator *iter, uint32_t key, int32_t *out) {
+  Tuple *t = dict_find(iter, key);
+  if (!t) return false;
+  *out = t->value->int32;
+  return true;
+}
+
+static void inbox_received_handler(DictionaryIterator *iter, void *context) {
+  WatchConfig cfg;
+  config_load(&cfg); /* start from existing settings - a field the page
+                       * doesn't send (e.g. it only changed the language)
+                       * keeps its previous value rather than resetting. */
+
+  int32_t v;
+  bool got_birth = false;
+  if (read_int(iter, MESSAGE_KEY_BIRTH_YEAR, &v)) { cfg.birth.year = v; got_birth = true; }
+  if (read_int(iter, MESSAGE_KEY_BIRTH_MONTH, &v)) { cfg.birth.month = v; got_birth = true; }
+  if (read_int(iter, MESSAGE_KEY_BIRTH_DAY, &v)) { cfg.birth.day = v; got_birth = true; }
+  if (read_int(iter, MESSAGE_KEY_BIRTH_HOUR, &v)) { cfg.birth.hour = v; got_birth = true; }
+  if (read_int(iter, MESSAGE_KEY_BIRTH_MINUTE, &v)) { cfg.birth.minute = v; got_birth = true; }
+  if (read_int(iter, MESSAGE_KEY_BIRTH_UTC_OFFSET_MINUTES, &v)) {
+    cfg.birth.utc_offset_hours = v / 60.0;
+    got_birth = true;
+  }
+  if (read_int(iter, MESSAGE_KEY_BIRTH_LAT_MICRODEG, &v)) {
+    cfg.birth.latitude = v / 1000000.0;
+    got_birth = true;
+  }
+  if (read_int(iter, MESSAGE_KEY_BIRTH_LON_MICRODEG, &v)) {
+    cfg.birth.longitude = v / 1000000.0;
+    got_birth = true;
+  }
+
+  Tuple *lang_tuple = dict_find(iter, MESSAGE_KEY_LANG);
+  if (lang_tuple) {
+    strncpy(cfg.lang, lang_tuple->value->cstring, sizeof(cfg.lang) - 1);
+    cfg.lang[sizeof(cfg.lang) - 1] = '\0';
+  }
+
+  if (read_int(iter, MESSAGE_KEY_NOTIFY_ENABLED, &v)) cfg.notify_enabled = (v != 0);
+  if (read_int(iter, MESSAGE_KEY_NOTIFY_HOUR, &v)) cfg.notify_hour = v;
+  if (read_int(iter, MESSAGE_KEY_NOTIFY_MINUTE, &v)) cfg.notify_minute = v;
+
+  /* Birth data is the one thing that makes a config submission "complete" -
+   * language/notification-only re-submissions (e.g. from a later re-open
+   * of the settings page) must not un-configure an already-set-up watch. */
+  if (got_birth) cfg.configured = true;
+
+  config_save(&cfg);
+  if (s_callback) s_callback(&cfg);
+}
+
+static void inbox_dropped_handler(AppMessageResult reason, void *context) {
+  APP_LOG(APP_LOG_LEVEL_ERROR, "AppMessage dropped: reason %d", (int)reason);
+}
+
+/* app_message_*_size_maximum() return the largest buffer the platform
+ * *could* hand out (8200 bytes each) - not a size to actually request.
+ * The real payload is ~150-200 bytes; 256 bytes each leaves headroom
+ * without eating into this app's ~12KB heap budget (see watch/README.md). */
+#define INBOX_SIZE 256
+#define OUTBOX_SIZE 256
+
+void app_message_init(ConfigUpdatedCallback on_config_updated) {
+  s_callback = on_config_updated;
+  app_message_register_inbox_received(inbox_received_handler);
+  app_message_register_inbox_dropped(inbox_dropped_handler);
+  app_message_open(INBOX_SIZE, OUTBOX_SIZE);
+}

watch/src/c/app_message.h

@@ -0,0 +1,20 @@
+#ifndef WATCH_APP_MESSAGE_H
+#define WATCH_APP_MESSAGE_H
+
+#include "config.h"
+
+/* Invoked with the freshly-saved config whenever a settings submission
+ * arrives from the config page (src/pkjs/index.js, task #43) - main.c
+ * uses this to recompute the reading and refresh/show the menu. */
+typedef void (*ConfigUpdatedCallback)(const WatchConfig *cfg);
+
+/* Registers the AppMessage inbox handler and opens the message buffers.
+ * Call once at startup, before app_event_loop(). Message keys
+ * (BIRTH_YEAR, BIRTH_UTC_OFFSET_MINUTES, LANG, NOTIFY_ENABLED, etc.) are
+ * declared in watch/package.json's "messageKeys" and turn into
+ * MESSAGE_KEY_* constants in the auto-generated message_keys.auto.h -
+ * see app_message.c's own comment on why latitude/longitude/utc offset
+ * travel as scaled integers rather than floats. */
+void app_message_init(ConfigUpdatedCallback on_config_updated);
+
+#endif

watch/src/c/config.c

@@ -0,0 +1,70 @@
+#include "config.h"
+
+#include <string.h>
+
+/* Persist keys. BirthData's latitude/longitude/utc_offset_hours are
+ * doubles, but Pebble's persist API has no float storage - stored as
+ * scaled int32s instead (microdegrees / minutes), matching how
+ * AppMessage carries the same fields from the config page - see
+ * app_message.c. */
+enum {
+  PKEY_CONFIGURED = 0,
+  PKEY_BIRTH_YEAR,
+  PKEY_BIRTH_MONTH,
+  PKEY_BIRTH_DAY,
+  PKEY_BIRTH_HOUR,
+  PKEY_BIRTH_MINUTE,
+  PKEY_BIRTH_UTC_OFFSET_MINUTES,
+  PKEY_BIRTH_LAT_MICRODEG,
+  PKEY_BIRTH_LON_MICRODEG,
+  PKEY_LANG,
+  PKEY_NOTIFY_ENABLED,
+  PKEY_NOTIFY_HOUR,
+  PKEY_NOTIFY_MINUTE,
+};
+
+void config_load(WatchConfig *out) {
+  memset(out, 0, sizeof *out);
+
+  out->configured = persist_exists(PKEY_CONFIGURED) && persist_read_bool(PKEY_CONFIGURED);
+  if (!out->configured) {
+    strcpy(out->lang, "en");
+    return;
+  }
+
+  out->birth.year = (int)persist_read_int(PKEY_BIRTH_YEAR);
+  out->birth.month = (int)persist_read_int(PKEY_BIRTH_MONTH);
+  out->birth.day = (int)persist_read_int(PKEY_BIRTH_DAY);
+  out->birth.hour = (int)persist_read_int(PKEY_BIRTH_HOUR);
+  out->birth.minute = (int)persist_read_int(PKEY_BIRTH_MINUTE);
+  out->birth.utc_offset_hours = (double)(int32_t)persist_read_int(PKEY_BIRTH_UTC_OFFSET_MINUTES) / 60.0;
+  out->birth.latitude = (double)(int32_t)persist_read_int(PKEY_BIRTH_LAT_MICRODEG) / 1000000.0;
+  out->birth.longitude = (double)(int32_t)persist_read_int(PKEY_BIRTH_LON_MICRODEG) / 1000000.0;
+
+  if (persist_read_string(PKEY_LANG, out->lang, sizeof out->lang) <= 0) {
+    strcpy(out->lang, "en");
+  }
+
+  out->notify_enabled = persist_read_bool(PKEY_NOTIFY_ENABLED);
+  out->notify_hour = (int)persist_read_int(PKEY_NOTIFY_HOUR);
+  out->notify_minute = (int)persist_read_int(PKEY_NOTIFY_MINUTE);
+}
+
+void config_save(const WatchConfig *cfg) {
+  persist_write_bool(PKEY_CONFIGURED, cfg->configured);
+
+  persist_write_int(PKEY_BIRTH_YEAR, cfg->birth.year);
+  persist_write_int(PKEY_BIRTH_MONTH, cfg->birth.month);
+  persist_write_int(PKEY_BIRTH_DAY, cfg->birth.day);
+  persist_write_int(PKEY_BIRTH_HOUR, cfg->birth.hour);
+  persist_write_int(PKEY_BIRTH_MINUTE, cfg->birth.minute);
+  persist_write_int(PKEY_BIRTH_UTC_OFFSET_MINUTES, (int32_t)(cfg->birth.utc_offset_hours * 60.0));
+  persist_write_int(PKEY_BIRTH_LAT_MICRODEG, (int32_t)(cfg->birth.latitude * 1000000.0));
+  persist_write_int(PKEY_BIRTH_LON_MICRODEG, (int32_t)(cfg->birth.longitude * 1000000.0));
+
+  persist_write_string(PKEY_LANG, cfg->lang);
+
+  persist_write_bool(PKEY_NOTIFY_ENABLED, cfg->notify_enabled);
+  persist_write_int(PKEY_NOTIFY_HOUR, cfg->notify_hour);
+  persist_write_int(PKEY_NOTIFY_MINUTE, cfg->notify_minute);
+}

watch/src/c/config.h

@@ -0,0 +1,31 @@
+#ifndef WATCH_CONFIG_H
+#define WATCH_CONFIG_H
+
+#include <pebble.h>
+
+#include "../../../engine/src/astro.h"
+
+/* Everything the watch needs that isn't computed fresh each day: birth
+ * data (the same fields as dist/user.properties), display language, and
+ * daily notification settings. Persisted on-watch via Pebble's own
+ * key-value persist API (see config.c) - no companion app, no server,
+ * matching the rest of this project's architecture. */
+typedef struct {
+  bool configured; /* false until the config page has been submitted once */
+  BirthData birth;
+  char lang[8]; /* e.g. "en", "de" - matches engine/i18n/<lang>.lang's own code */
+  bool notify_enabled;
+  int notify_hour;   /* 0-23, the watch's own local wall-clock time (i.e.
+                       * localtime(), not birth.utc_offset_hours - the
+                       * user's current timezone, synced from their phone,
+                       * not necessarily their birth location's). */
+  int notify_minute; /* 0-59 */
+} WatchConfig;
+
+/* Fills `out` with the persisted config, or a safe all-zero/`configured
+ * = false` default if nothing has been saved yet (first run). */
+void config_load(WatchConfig *out);
+
+void config_save(const WatchConfig *cfg);
+
+#endif

watch/src/c/i18n_tables.h

@@ -0,0 +1,16 @@
+#ifndef WATCH_I18N_TABLES_H
+#define WATCH_I18N_TABLES_H
+
+/* Points i18n_get() (engine/src/i18n.h) at the compiled-in translation
+ * table for `lang_code`, generated at build time from engine/i18n's
+ * .lang files by watch/scripts/gen_i18n_tables.py into
+ * i18n_tables.auto.c - see that script's own doc comment for the format
+ * and why English is deliberately not one of the compiled tables.
+ * Passing "en", NULL, or any code with no matching .lang file resets to
+ * no table at all, so every i18n_get() call falls through to its
+ * built-in English fallback text - the correct behavior when a user
+ * switches the watch's language setting back to English at runtime,
+ * not just on first load. */
+void watch_i18n_load(const char *lang_code);
+
+#endif

watch/src/c/main.c

@@ -0,0 +1,50 @@
+#include <pebble.h>
+
+#include "../../../engine/src/i18n.h"
+#include "app_message.h"
+#include "config.h"
+#include "i18n_tables.h"
+#include "reading_state.h"
+#include "ui_menu_window.h"
+#include "ui_text_window.h"
+
+static WatchConfig s_config;
+
+static void show_setup_required(void) {
+  text_window_push(i18n_get("ui.setup_required_title", "Setup Required"),
+                    i18n_get("ui.setup_required_body",
+                             "Open this app's settings from the Pebble mobile app to add your "
+                             "birth details, then reopen Deck in a Dash."));
+}
+
+static void on_config_updated(const WatchConfig *cfg) {
+  bool was_configured = s_config.configured;
+  s_config = *cfg;
+  watch_i18n_load(s_config.lang);
+
+  if (!s_config.configured) return;
+
+  reading_state_recompute(&s_config.birth);
+  if (was_configured) {
+    menu_window_reload();
+  } else {
+    menu_window_push();
+  }
+}
+
+int main(void) {
+  config_load(&s_config);
+  watch_i18n_load(s_config.lang);
+  app_message_init(on_config_updated);
+
+  if (s_config.configured) {
+    reading_state_recompute(&s_config.birth);
+    menu_window_push();
+  } else {
+    show_setup_required();
+  }
+
+  app_event_loop();
+
+  menu_window_deinit();
+}

watch/src/c/reading_state.c

@@ -0,0 +1,27 @@
+#include "reading_state.h"
+
+#include <stdio.h>
+
+static DailyReading s_reading;
+static DailyInterpretation s_interp;
+
+void reading_state_recompute(const BirthData *birth) {
+  time_t now = time(NULL);
+  /* Plain gmtime() (not the POSIX-only gmtime_r()), used immediately -
+   * same justification as astro.c's own time_from_unix(). */
+  struct tm *utc = gmtime(&now);
+
+  char seed[16];
+  snprintf(seed, sizeof seed, "%04d-%02d-%02d", utc->tm_year + 1900, utc->tm_mon + 1, utc->tm_mday);
+
+  reading_generate(seed, birth, now, &s_reading);
+  interpret_daily_reading(&s_reading, &s_interp);
+}
+
+const DailyReading *reading_state_get_reading(void) {
+  return &s_reading;
+}
+
+const DailyInterpretation *reading_state_get_interpretation(void) {
+  return &s_interp;
+}

watch/src/c/reading_state.h

@@ -0,0 +1,19 @@
+#ifndef WATCH_READING_STATE_H
+#define WATCH_READING_STATE_H
+
+#include "../../../engine/src/reading.h"
+#include "../../../interpreter/src/significance.h"
+
+/* Recomputes today's reading (astro + tarot + interpretation) from
+ * `birth`, using the watch's current clock: today's UTC date as the
+ * tarot seed (same convention as dist/run-engine.sh - see CLAUDE.md's
+ * "Build & run") and the current moment for the transit snapshot. Safe
+ * to call again later (e.g. the day rolled over while the app stayed
+ * open) - overwrites the previous result in place. */
+void reading_state_recompute(const BirthData *birth);
+
+/* Valid only after at least one reading_state_recompute() call. */
+const DailyReading *reading_state_get_reading(void);
+const DailyInterpretation *reading_state_get_interpretation(void);
+
+#endif

watch/src/c/resource_map.c

@@ -0,0 +1,31 @@
+#include "resource_map.h"
+
+#include <pebble.h>
+
+uint32_t card_resource_id(TarotCard card) {
+  switch (card) {
+    case CARD_FOOL: return RESOURCE_ID_IMG_CARD_FOOL;
+    case CARD_MAGICIAN: return RESOURCE_ID_IMG_CARD_MAGICIAN;
+    case CARD_HIGH_PRIESTESS: return RESOURCE_ID_IMG_CARD_HIGH_PRIESTESS;
+    case CARD_EMPRESS: return RESOURCE_ID_IMG_CARD_EMPRESS;
+    case CARD_EMPEROR: return RESOURCE_ID_IMG_CARD_EMPEROR;
+    case CARD_HIEROPHANT: return RESOURCE_ID_IMG_CARD_HIEROPHANT;
+    case CARD_LOVERS: return RESOURCE_ID_IMG_CARD_LOVERS;
+    case CARD_CHARIOT: return RESOURCE_ID_IMG_CARD_CHARIOT;
+    case CARD_STRENGTH: return RESOURCE_ID_IMG_CARD_STRENGTH;
+    case CARD_HERMIT: return RESOURCE_ID_IMG_CARD_HERMIT;
+    case CARD_WHEEL_OF_FORTUNE: return RESOURCE_ID_IMG_CARD_WHEEL_OF_FORTUNE;
+    case CARD_JUSTICE: return RESOURCE_ID_IMG_CARD_JUSTICE;
+    case CARD_HANGED_MAN: return RESOURCE_ID_IMG_CARD_HANGED_MAN;
+    case CARD_DEATH: return RESOURCE_ID_IMG_CARD_DEATH;
+    case CARD_TEMPERANCE: return RESOURCE_ID_IMG_CARD_TEMPERANCE;
+    case CARD_DEVIL: return RESOURCE_ID_IMG_CARD_DEVIL;
+    case CARD_TOWER: return RESOURCE_ID_IMG_CARD_TOWER;
+    case CARD_STAR: return RESOURCE_ID_IMG_CARD_STAR;
+    case CARD_MOON: return RESOURCE_ID_IMG_CARD_MOON;
+    case CARD_SUN: return RESOURCE_ID_IMG_CARD_SUN;
+    case CARD_JUDGEMENT: return RESOURCE_ID_IMG_CARD_JUDGEMENT;
+    case CARD_WORLD: return RESOURCE_ID_IMG_CARD_WORLD;
+  }
+  return RESOURCE_ID_IMG_CARD_FOOL; /* unreachable for a valid TarotCard */
+}

watch/src/c/resource_map.h

@@ -0,0 +1,18 @@
+#ifndef WATCH_RESOURCE_MAP_H
+#define WATCH_RESOURCE_MAP_H
+
+#include <stdint.h>
+
+#include "../../../engine/src/tarot.h"
+
+/* Maps a TarotCard to its compiled-in bitmap resource ID. Each of
+ * watch/package.json's "resources.media" entries is named
+ * IMG_CARD_<SLUG UPPERCASE>, matching engine/src/tarot_data.c's own
+ * k_card_slug table (see watch/scripts/gen_card_images.py, which
+ * generates the underlying PNGs with the same slugs) - Pebble's build
+ * turns each into a RESOURCE_ID_IMG_CARD_<SLUG> macro in the
+ * auto-generated resource_ids.auto.h, which this function is the one
+ * place in the app that switches over. */
+uint32_t card_resource_id(TarotCard card);
+
+#endif

watch/src/c/ui_card_window.c

@@ -0,0 +1,78 @@
+#include "ui_card_window.h"
+
+#include <pebble.h>
+
+#include "resource_map.h"
+
+/* Matches the fixed size gen_card_images.py resizes every card to. */
+#define IMAGE_WIDTH 72
+#define IMAGE_HEIGHT 120
+
+typedef struct {
+  TarotCard card;
+  char *text; /* title + "\n" + body, combined into one scrollable block */
+  GBitmap *bitmap;
+  BitmapLayer *bitmap_layer;
+  ScrollLayer *scroll_layer;
+  TextLayer *text_layer;
+} CardWindowState;
+
+static void window_load(Window *window) {
+  CardWindowState *state = window_get_user_data(window);
+  Layer *window_layer = window_get_root_layer(window);
+  GRect bounds = layer_get_bounds(window_layer);
+
+  state->bitmap = gbitmap_create_with_resource(card_resource_id(state->card));
+  int image_x = (bounds.size.w - IMAGE_WIDTH) / 2;
+  state->bitmap_layer = bitmap_layer_create(GRect(image_x, 0, IMAGE_WIDTH, IMAGE_HEIGHT));
+  bitmap_layer_set_bitmap(state->bitmap_layer, state->bitmap);
+  bitmap_layer_set_alignment(state->bitmap_layer, GAlignCenter);
+  layer_add_child(window_layer, bitmap_layer_get_layer(state->bitmap_layer));
+
+  GRect scroll_bounds = GRect(0, IMAGE_HEIGHT, bounds.size.w, bounds.size.h - IMAGE_HEIGHT);
+  state->scroll_layer = scroll_layer_create(scroll_bounds);
+  scroll_layer_set_click_config_onto_window(state->scroll_layer, window);
+
+  state->text_layer = text_layer_create(GRect(0, 0, scroll_bounds.size.w, 2000));
+  text_layer_set_font(state->text_layer, fonts_get_system_font(FONT_KEY_GOTHIC_18));
+  text_layer_set_text(state->text_layer, state->text);
+  text_layer_set_overflow_mode(state->text_layer, GTextOverflowModeWordWrap);
+
+  GSize content_size = text_layer_get_content_size(state->text_layer);
+  content_size.w = scroll_bounds.size.w;
+  content_size.h += 4;
+  text_layer_set_size(state->text_layer, content_size);
+  scroll_layer_set_content_size(state->scroll_layer, content_size);
+
+  scroll_layer_add_child(state->scroll_layer, text_layer_get_layer(state->text_layer));
+  layer_add_child(window_layer, scroll_layer_get_layer(state->scroll_layer));
+}
+
+static void window_unload(Window *window) {
+  CardWindowState *state = window_get_user_data(window);
+  bitmap_layer_destroy(state->bitmap_layer);
+  gbitmap_destroy(state->bitmap);
+  text_layer_destroy(state->text_layer);
+  scroll_layer_destroy(state->scroll_layer);
+  free(state->text);
+  free(state);
+  window_destroy(window);
+}
+
+void card_window_push(TarotCard card, const char *title, const char *body) {
+  CardWindowState *state = malloc(sizeof(CardWindowState));
+  memset(state, 0, sizeof *state);
+  state->card = card;
+
+  size_t len = strlen(title) + 1 + strlen(body) + 1;
+  state->text = malloc(len);
+  snprintf(state->text, len, "%s\n%s", title, body);
+
+  Window *window = window_create();
+  window_set_user_data(window, state);
+  window_set_window_handlers(window, (WindowHandlers){
+    .load = window_load,
+    .unload = window_unload,
+  });
+  window_stack_push(window, true);
+}

watch/src/c/ui_card_window.h

@@ -0,0 +1,12 @@
+#ifndef WATCH_UI_CARD_WINDOW_H
+#define WATCH_UI_CARD_WINDOW_H
+
+#include "../../../engine/src/tarot.h"
+
+/* Pushes a window showing `card`'s art (via resource_map.h) pinned at
+ * the top, with `title` and `body` below it as scrollable text (e.g. the
+ * Celtic Cross position name + orientation, and the position description
+ * + card meaning). Copies both strings, same as text_window_push(). */
+void card_window_push(TarotCard card, const char *title, const char *body);
+
+#endif

watch/src/c/ui_menu_window.c

@@ -0,0 +1,191 @@
+#include "ui_menu_window.h"
+
+#include <pebble.h>
+
+#include "../../../engine/src/i18n.h"
+#include "../../../interpreter/src/guidance.h"
+#include "../../../interpreter/src/narrative.h"
+#include "reading_state.h"
+#include "ui_card_window.h"
+#include "ui_text_window.h"
+
+typedef enum {
+  SECTION_TODAY = 0,
+  SECTION_TRANSITS,
+  SECTION_CELTIC_CROSS,
+  NUM_SECTIONS
+} MenuSection;
+
+static Window *s_window;
+static MenuLayer *s_menu_layer;
+
+/* Small local day-level name table, same duplication policy as
+ * interpreter/src/main.c's own day_level_name() - see significance.c's
+ * comment on why each independently-testable/linkable module keeps its
+ * own copy rather than sharing one across translation units that aren't
+ * otherwise coupled. */
+static const char *day_level_name(DaySignificance level) {
+  switch (level) {
+    case DAY_QUIET: return i18n_get("interp.day_level.quiet", "Quiet");
+    case DAY_NOTABLE: return i18n_get("interp.day_level.notable", "Notable");
+    case DAY_SIGNIFICANT: return i18n_get("interp.day_level.significant", "Significant");
+    case DAY_MAJOR: return i18n_get("interp.day_level.major", "Major");
+    default: return "";
+  }
+}
+
+static const char *reversed_marker(bool reversed) {
+  return reversed ? i18n_get("ui.reversed", "(Reversed)") : "";
+}
+
+static uint16_t get_num_sections_callback(MenuLayer *menu_layer, void *data) {
+  return NUM_SECTIONS;
+}
+
+static uint16_t get_num_rows_callback(MenuLayer *menu_layer, uint16_t section_index, void *data) {
+  const DailyInterpretation *interp = reading_state_get_interpretation();
+  switch (section_index) {
+    case SECTION_TODAY: return 1;
+    case SECTION_TRANSITS: return interp->top_item_count > 0 ? interp->top_item_count : 1;
+    case SECTION_CELTIC_CROSS: return TAROT_SPREAD_SIZE;
+    default: return 0;
+  }
+}
+
+static int16_t get_header_height_callback(MenuLayer *menu_layer, uint16_t section_index, void *data) {
+  return MENU_CELL_BASIC_HEADER_HEIGHT;
+}
+
+static void draw_header_callback(GContext *ctx, const Layer *cell_layer, uint16_t section_index, void *data) {
+  const char *title = "";
+  switch (section_index) {
+    case SECTION_TODAY: title = i18n_get("interp.heading_day_significance", "Day Significance"); break;
+    case SECTION_TRANSITS: title = i18n_get("interp.heading_transits", "Significant Transits"); break;
+    case SECTION_CELTIC_CROSS: title = i18n_get("ui.celtic_cross", "Celtic Cross"); break;
+  }
+  menu_cell_basic_header_draw(ctx, cell_layer, title);
+}
+
+static void draw_row_callback(GContext *ctx, const Layer *cell_layer, MenuIndex *cell_index, void *data) {
+  const DailyReading *reading = reading_state_get_reading();
+  const DailyInterpretation *interp = reading_state_get_interpretation();
+
+  char title[48];
+  char subtitle[64];
+
+  switch (cell_index->section) {
+    case SECTION_TODAY:
+      snprintf(title, sizeof title, "%s (%d/%d)", day_level_name(interp->day_level),
+               interp->day_level + 1, DAY_SIGNIFICANCE_COUNT);
+      menu_cell_basic_draw(ctx, cell_layer, title, NULL, NULL);
+      break;
+
+    case SECTION_TRANSITS:
+      if (interp->top_item_count == 0) {
+        menu_cell_basic_draw(ctx, cell_layer,
+                              i18n_get("interp.no_notable_transits", "No notable transits today."),
+                              NULL, NULL);
+        break;
+      }
+      {
+        const Aspect *a = &interp->top_items[cell_index->row].aspect;
+        snprintf(title, sizeof title, "%s %s", i18n_get("ui.transiting", "Transiting"),
+                 astro_body_name(a->transiting_planet));
+        snprintf(subtitle, sizeof subtitle, "%s %s %s", astro_aspect_name(a->type),
+                 i18n_get("ui.natal", "natal"), astro_body_name(a->natal_planet));
+        menu_cell_basic_draw(ctx, cell_layer, title, subtitle, NULL);
+      }
+      break;
+
+    case SECTION_CELTIC_CROSS: {
+      const TarotDraw *draw = &reading->spread.positions[cell_index->row];
+      snprintf(title, sizeof title, "%s", tarot_position_name((CelticCrossPosition)cell_index->row));
+      snprintf(subtitle, sizeof subtitle, "%s %s", tarot_card_name(draw->card),
+               reversed_marker(draw->reversed));
+      menu_cell_basic_draw(ctx, cell_layer, title, subtitle, NULL);
+      break;
+    }
+  }
+}
+
+static void select_callback(MenuLayer *menu_layer, MenuIndex *cell_index, void *data) {
+  const DailyReading *reading = reading_state_get_reading();
+  const DailyInterpretation *interp = reading_state_get_interpretation();
+
+  switch (cell_index->section) {
+    case SECTION_TODAY: {
+      char body[GUIDANCE_TEXT_MAX];
+      guidance_write(body, sizeof body, "", interp, &reading->spread);
+      text_window_push(i18n_get("interp.heading_day_significance", "Day Significance"), body);
+      break;
+    }
+
+    case SECTION_TRANSITS: {
+      if (interp->top_item_count == 0) break;
+      const Aspect *a = &interp->top_items[cell_index->row].aspect;
+      char title[48];
+      snprintf(title, sizeof title, "%s %s", i18n_get("ui.transiting", "Transiting"),
+               astro_body_name(a->transiting_planet));
+      char body[NARRATIVE_TEXT_MAX];
+      narrative_write(body, sizeof body, "", a, reading->transits.bodies[a->transiting_planet].house);
+      text_window_push(title, body);
+      break;
+    }
+
+    case SECTION_CELTIC_CROSS: {
+      const TarotDraw *draw = &reading->spread.positions[cell_index->row];
+      char title[64];
+      snprintf(title, sizeof title, "%s: %s %s",
+               tarot_position_name((CelticCrossPosition)cell_index->row),
+               tarot_card_name(draw->card), reversed_marker(draw->reversed));
+      char body[600];
+      snprintf(body, sizeof body, "%s\n\n%s",
+               tarot_position_description((CelticCrossPosition)cell_index->row),
+               tarot_card_meaning(draw->card, draw->reversed));
+      card_window_push(draw->card, title, body);
+      break;
+    }
+  }
+}
+
+static void window_load(Window *window) {
+  Layer *window_layer = window_get_root_layer(window);
+  GRect bounds = layer_get_bounds(window_layer);
+
+  s_menu_layer = menu_layer_create(bounds);
+  menu_layer_set_callbacks(s_menu_layer, NULL, (MenuLayerCallbacks){
+    .get_num_sections = get_num_sections_callback,
+    .get_num_rows = get_num_rows_callback,
+    .get_header_height = get_header_height_callback,
+    .draw_header = draw_header_callback,
+    .draw_row = draw_row_callback,
+    .select_click = select_callback,
+  });
+  menu_layer_set_click_config_onto_window(s_menu_layer, window);
+  layer_add_child(window_layer, menu_layer_get_layer(s_menu_layer));
+}
+
+static void window_unload(Window *window) {
+  menu_layer_destroy(s_menu_layer);
+  s_menu_layer = NULL;
+}
+
+void menu_window_push(void) {
+  if (!s_window) {
+    s_window = window_create();
+    window_set_window_handlers(s_window, (WindowHandlers){
+      .load = window_load,
+      .unload = window_unload,
+    });
+  }
+  window_stack_push(s_window, true);
+}
+
+void menu_window_reload(void) {
+  if (s_menu_layer) menu_layer_reload_data(s_menu_layer);
+}
+
+void menu_window_deinit(void) {
+  if (s_window) window_destroy(s_window);
+  s_window = NULL;
+}

watch/src/c/ui_menu_window.h

@@ -0,0 +1,19 @@
+#ifndef WATCH_UI_MENU_WINDOW_H
+#define WATCH_UI_MENU_WINDOW_H
+
+/* The app's root screen: a 3-section MenuLayer (Day Significance /
+ * Significant Transits / Celtic Cross) reading directly from
+ * reading_state.h's current reading - see reading.h's own doc comment
+ * ("walks the returned struct directly to lay out its own screens").
+ * Selecting a row pushes a detail screen (ui_text_window.h for prose,
+ * ui_card_window.h for a Celtic Cross position). A persistent singleton -
+ * created once and left at the bottom of the window stack; call
+ * menu_window_push() once at startup (and again if the day rolls over
+ * and the underlying reading changes - the MenuLayer re-reads
+ * reading_state.h on every redraw, so no explicit refresh call is
+ * needed beyond menu_layer_reload_data()). */
+void menu_window_push(void);
+void menu_window_reload(void);
+void menu_window_deinit(void);
+
+#endif

watch/src/c/ui_text_window.c

@@ -0,0 +1,74 @@
+#include "ui_text_window.h"
+
+#include <pebble.h>
+
+#define TITLE_HEIGHT 24
+
+typedef struct {
+  char *title;
+  char *body;
+  TextLayer *title_layer;
+  ScrollLayer *scroll_layer;
+  TextLayer *body_layer;
+} TextWindowState;
+
+static void window_load(Window *window) {
+  TextWindowState *state = window_get_user_data(window);
+  Layer *window_layer = window_get_root_layer(window);
+  GRect bounds = layer_get_bounds(window_layer);
+
+  state->title_layer = text_layer_create(GRect(0, 0, bounds.size.w, TITLE_HEIGHT));
+  text_layer_set_font(state->title_layer, fonts_get_system_font(FONT_KEY_GOTHIC_18_BOLD));
+  text_layer_set_text(state->title_layer, state->title);
+  text_layer_set_overflow_mode(state->title_layer, GTextOverflowModeTrailingEllipsis);
+  layer_add_child(window_layer, text_layer_get_layer(state->title_layer));
+
+  GRect scroll_bounds = GRect(0, TITLE_HEIGHT, bounds.size.w, bounds.size.h - TITLE_HEIGHT);
+  state->scroll_layer = scroll_layer_create(scroll_bounds);
+  scroll_layer_set_click_config_onto_window(state->scroll_layer, window);
+
+  /* Tall placeholder height so text_layer_get_content_size() below can
+   * measure the real wrapped height - standard Pebble ScrollLayer
+   * pattern (a TextLayer taller than its content just clips nothing). */
+  state->body_layer = text_layer_create(GRect(0, 0, scroll_bounds.size.w, 2000));
+  text_layer_set_font(state->body_layer, fonts_get_system_font(FONT_KEY_GOTHIC_18));
+  text_layer_set_text(state->body_layer, state->body);
+  text_layer_set_overflow_mode(state->body_layer, GTextOverflowModeWordWrap);
+
+  GSize content_size = text_layer_get_content_size(state->body_layer);
+  content_size.w = scroll_bounds.size.w;
+  content_size.h += 4;
+  text_layer_set_size(state->body_layer, content_size);
+  scroll_layer_set_content_size(state->scroll_layer, content_size);
+
+  scroll_layer_add_child(state->scroll_layer, text_layer_get_layer(state->body_layer));
+  layer_add_child(window_layer, scroll_layer_get_layer(state->scroll_layer));
+}
+
+static void window_unload(Window *window) {
+  TextWindowState *state = window_get_user_data(window);
+  text_layer_destroy(state->title_layer);
+  text_layer_destroy(state->body_layer);
+  scroll_layer_destroy(state->scroll_layer);
+  free(state->title);
+  free(state->body);
+  free(state);
+  window_destroy(window);
+}
+
+void text_window_push(const char *title, const char *body) {
+  TextWindowState *state = malloc(sizeof(TextWindowState));
+  memset(state, 0, sizeof *state);
+  state->title = malloc(strlen(title) + 1);
+  strcpy(state->title, title);
+  state->body = malloc(strlen(body) + 1);
+  strcpy(state->body, body);
+
+  Window *window = window_create();
+  window_set_user_data(window, state);
+  window_set_window_handlers(window, (WindowHandlers){
+    .load = window_load,
+    .unload = window_unload,
+  });
+  window_stack_push(window, true);
+}

watch/src/c/ui_text_window.h

@@ -0,0 +1,16 @@
+#ifndef WATCH_UI_TEXT_WINDOW_H
+#define WATCH_UI_TEXT_WINDOW_H
+
+/* Pushes a scrollable full-screen text window: `title` as a bold header,
+ * `body` below it, word-wrapped and scrollable with the up/down buttons.
+ * Used for every screen that's just prose (Summary/Guidance, a single
+ * transit's narrative) - the Celtic Cross card screens use
+ * ui_card_window.h instead, which also shows the card's image.
+ *
+ * Copies both strings internally (into the pushed window's own heap
+ * state, freed when it's popped), so the caller's buffer doesn't need to
+ * outlive the call - every caller so far builds `title`/`body` in a
+ * short-lived local buffer right before pushing. */
+void text_window_push(const char *title, const char *body);
+
+#endif

watch/src/pkjs/index.js

@@ -0,0 +1,5 @@
+// Skeleton only - the real config webview (birth data/language/
+// notification settings) is built out in a later task, see CLAUDE.md/
+// TaskList. No companion app, no server: this file's only future job is
+// showConfiguration/webviewclosed handling for a self-contained `data:`
+// URI settings form.

watch/wscript

@@ -0,0 +1,96 @@
+#
+# Pebble app build rules for Deck in a Dash.
+#
+# Unlike a typical `pebble new-project` skeleton, this app's C sources
+# aren't all under src/c/ - most of the actual reading logic lives in
+# ../engine/src/ (rng, tarot, tarot_data, astro, i18n, reading) and is
+# shared byte-for-byte with the desktop deck-engine/interpreter-cli
+# binaries (see the root CLAUDE.md's "Portability to the watch"
+# section). build() below explicitly lists the engine source files this
+# app needs and glues them onto src/c/**/*.c's own sources - it does NOT
+# glob ../engine/src/*.c wholesale, because that directory also contains
+# reading.c's desktop-only fprintf-based print functions (compiled out
+# under #ifndef PBL_SDK_3, so harmless to include) but must never pull in
+# engine/third_party/astronomy/ (the vendored high-precision ephemeris,
+# ~127KB compiled - alone bigger than a whole Pebble app's 64KB
+# code+data+bss budget). This app uses lowprec_ephemeris.c instead - see
+# that file's own header comment.
+import os.path
+import subprocess
+import sys
+
+top = '.'
+out = 'build'
+
+# Engine source files this app links in, relative to ../engine/src/ -
+# see the module comment above for why this is an explicit list rather
+# than a glob.
+ENGINE_SRCS = [
+    'rng.c',
+    'tarot.c',
+    'tarot_data.c',
+    'astro.c',
+    'i18n.c',
+    'reading.c',
+    'lowprec_ephemeris.c',
+]
+
+# interpreter/'s significance/narrative/guidance scoring and text - see
+# CLAUDE.md's "Interpretation" section. Unlike the desktop interpreter-cli
+# (which deliberately keeps these header-only against the engine, for
+# independent testability without a real ephemeris - see significance.h's
+# own comment), the watch links their real .c implementations straight
+# into the same binary as the engine above: there's no deck-engine/
+# interpreter-cli JSON pipe to speak of on a single device, just one
+# process computing and immediately rendering its own reading. json.c/
+# reading_io.c (the JSON parser/loader) are never linked - the watch has
+# no JSON to parse, it calls reading_generate() directly.
+INTERP_SRCS = [
+    'significance.c',
+    'narrative.c',
+    'guidance.c',
+]
+
+
+def options(ctx):
+    ctx.load('pebble_sdk')
+
+
+def configure(ctx):
+    ctx.load('pebble_sdk')
+
+
+def build(ctx):
+    ctx.load('pebble_sdk')
+
+    # Regenerate src/c/i18n_tables.auto.c from engine/i18n/*.lang, and
+    # resources/img/*.png from res/img/*.jpeg, before compiling/bundling
+    # anything - see each script's own doc comment. Both run eagerly (not
+    # as waf Tasks) since the bundle step below depends on their output
+    # existing; gen_card_images.py skips any card whose PNG is already
+    # up to date, so this stays cheap on repeat builds. Requires Pillow
+    # (`pip install Pillow`) - see watch/README.md.
+    subprocess.check_call([sys.executable, 'scripts/gen_i18n_tables.py'])
+    subprocess.check_call([sys.executable, 'scripts/gen_card_images.py'])
+
+    engine_dir = ctx.path.parent.find_dir('engine/src')
+    engine_nodes = [engine_dir.find_node(name) for name in ENGINE_SRCS]
+    interp_dir = ctx.path.parent.find_dir('interpreter/src')
+    interp_nodes = [interp_dir.find_node(name) for name in INTERP_SRCS]
+
+    binaries = []
+    cached_env = ctx.env
+    for platform in ctx.env.TARGET_PLATFORMS:
+        ctx.env = ctx.all_envs[platform]
+        ctx.set_group(ctx.env.PLATFORM_NAME)
+        app_elf = '{}/pebble-app.elf'.format(ctx.env.BUILD_DIR)
+        app_sources = ctx.path.ant_glob('src/c/**/*.c') + engine_nodes + interp_nodes
+        ctx.pbl_build(source=app_sources, target=app_elf, bin_type='app')
+        binaries.append({'platform': platform, 'app_elf': app_elf})
+    ctx.env = cached_env
+
+    ctx.set_group('bundle')
+    ctx.pbl_bundle(binaries=binaries,
+                    js=ctx.path.ant_glob(['src/pkjs/**/*.js',
+                                           'src/pkjs/**/*.json']),
+                    js_entry_file='src/pkjs/index.js')