Add astrological houses to natal chart and daily transits

Every planet position now carries its whole-sign house (1-12); transits
report the natal house each transiting planet currently occupies rather
than a fresh "houses for right now" chart, matching how transits are
normally read. Surfaced in both text and HTML output, fully translated.

CLAUDE.md

@@ -120,6 +120,13 @@ you touch this function, keep the intermediate type 64-bit.
   Engine has no Ascendant function; it's computed directly in `astro.c`
   from sidereal time + a standard low-precision obliquity polynomial +
   the RAMC/obliquity/latitude identity (Duffett-Smith & Zwart).
+- Every `PlanetPosition` (`astro.h`) carries a whole-sign `house` (1-12),
+  via `assign_houses()`/`whole_sign_house()`. **`DailyTransits.bodies[*].house`
+  is always relative to the *natal* Ascendant**, not a fresh "houses for
+  right now" chart — that's the standard, personalized way transits are
+  read (e.g. "transiting Jupiter is in your 5th house"), and it's why
+  `astro_compute_daily_transits` takes the natal chart as a parameter in
+  the first place (also used for aspect detection).
 - Aspects (conjunction/sextile/square/trine/opposition) use an 8° orb
   when a luminary (Sun/Moon) is involved, 6° otherwise.
 

README.md

@@ -1,5 +1,5 @@
 <p align="center">
-  <img src="res/logo.png" width="200" alt="Deck in a Dash logo">
+  <img src="res/logo.png" width="290" alt="Deck in a Dash logo">
 </p>
 
 # Deck in a Dash

docs/input-output-format.md

@@ -91,10 +91,13 @@ typedef struct {
 ```
 
 - **`NatalChart`** (`astro.h`): `bodies[10]` (Sun..Pluto, each a sign +
-  degree-in-sign + raw ecliptic longitude), `ascendant_longitude`,
-  `houses[12]` (whole-sign: `houses[0]` is the Ascendant's sign).
+  degree-in-sign + raw ecliptic longitude + whole-sign `house` 1-12),
+  `ascendant_longitude`, `houses[12]` (whole-sign: `houses[0]` is the
+  Ascendant's sign).
 - **`DailyTransits`** (`astro.h`): `bodies[10]` (today's positions, same
-  shape as above), `moon_phase` (one of 8 named phases), `aspects[]` +
+  shape as above — `house` here is the natal chart's house the
+  transiting planet currently occupies, not a fresh "houses for right
+  now" chart), `moon_phase` (one of 8 named phases), `aspects[]` +
   `aspect_count` (each aspect names a transiting planet, a natal planet,
   an `AspectType` — conjunction/sextile/square/trine/opposition — and
   the orb in degrees).
@@ -107,22 +110,22 @@ typedef struct {
 ### `--format text`
 
 Four `=====`-delimited sections, in order: natal chart (each body's sign
-+ degree, then the Ascendant), today's sky (Moon phase, then each body's
-transiting position), today's aspects to the natal chart (one line per
-aspect, with orb), and the Celtic Cross (one block per position: name,
-card, `(Reversed)` if applicable, the position's meaning, then the
-card's meaning).
++ degree + house, then the Ascendant), today's sky (Moon phase, then each
+body's transiting position + the natal house it currently occupies),
+today's aspects to the natal chart (one line per aspect, with orb), and
+the Celtic Cross (one block per position: name, card, `(Reversed)` if
+applicable, the position's meaning, then the card's meaning).
 
 ```
 ===== Natal Chart =====
-Sun       23.5° Taurus
-Moon      15.2° Capricorn
+Sun       23.5° Taurus      (House 3)
+Moon      15.2° Capricorn   (House 11)
 ...
 Ascendant  18.4° Pisces
 
 ===== Today's Sky =====
 Moon phase: Waning Gibbous
-Sun       11.5° Cancer
+Sun       11.5° Cancer      (House 5)
 ...
 
 ===== Today's Aspects to Natal Chart =====

engine/i18n/de.lang

@@ -14,6 +14,7 @@ ui.todays_sky=Heutiger Himmel
 ui.todays_aspects=Heutige Aspekte zum Geburtshoroskop
 ui.celtic_cross=Keltisches Kreuz
 ui.ascendant=Aszendent
+ui.house=Haus
 ui.moon_phase=Mondphase:
 ui.no_aspects=(keine im Orbis)
 ui.reversed=(Umgekehrt)

engine/i18n/en.lang

@@ -21,6 +21,7 @@ ui.todays_sky=Today's Sky
 ui.todays_aspects=Today's Aspects to Natal Chart
 ui.celtic_cross=Celtic Cross
 ui.ascendant=Ascendant
+ui.house=House
 ui.moon_phase=Moon phase:
 ui.no_aspects=(none within orb)
 ui.reversed=(Reversed)

engine/src/astro.c

@@ -86,6 +86,20 @@ static void compute_body_positions(astro_time_t time, PlanetPosition out[NUM_BOD
   }
 }
 
+/* Whole-sign house number (1-12) for `sign`, counting from `ascendant_sign`
+ * as house 1. Used both for the natal chart's own placements and (with the
+ * natal ascendant) for today's transiting planets - see the `house` field
+ * comment in astro.h for why transits use the natal houses, not their own. */
+static int whole_sign_house(ZodiacSign sign, ZodiacSign ascendant_sign) {
+  return ((int)sign - (int)ascendant_sign + 12) % 12 + 1;
+}
+
+static void assign_houses(PlanetPosition bodies[NUM_BODIES], ZodiacSign ascendant_sign) {
+  for (int b = 0; b < NUM_BODIES; b++) {
+    bodies[b].house = whole_sign_house(bodies[b].sign, ascendant_sign);
+  }
+}
+
 void astro_compute_natal_chart(const BirthData *birth, NatalChart *out) {
   astro_time_t time = time_from_birth(birth);
 
@@ -96,6 +110,8 @@ void astro_compute_natal_chart(const BirthData *birth, NatalChart *out) {
   for (int house = 0; house < 12; house++) {
     out->houses[house] = (ZodiacSign)((ascendant_sign + house) % 12);
   }
+
+  assign_houses(out->bodies, out->houses[0]);
 }
 
 static MoonPhaseName moon_phase_from_angle(double angle_deg) {
@@ -129,6 +145,7 @@ void astro_compute_daily_transits(time_t utc_moment, const NatalChart *natal,
   astro_time_t time = time_from_unix(utc_moment);
 
   compute_body_positions(time, out->bodies);
+  assign_houses(out->bodies, natal->houses[0]);
 
   astro_angle_result_t phase = Astronomy_MoonPhase(time);
   out->moon_phase = moon_phase_from_angle(phase.angle);

engine/src/astro.h

@@ -60,6 +60,11 @@ typedef struct {
   double ecliptic_longitude; /* geocentric, degrees, [0, 360) */
   ZodiacSign sign;
   double degree_in_sign; /* [0, 30) */
+  int house; /* 1-12, whole-sign, always relative to the natal Ascendant -
+              * for DailyTransits.bodies this places today's transiting
+              * planets in the natal chart's own houses (the standard,
+              * personalized way to read transits), not a fresh "houses
+              * for right now" chart. */
 } PlanetPosition;
 
 typedef struct {

engine/src/reading.c

@@ -18,7 +18,8 @@ void reading_generate(const char *tarot_seed, const BirthData *birth,
 }
 
 static void print_position_deg(FILE *out, const PlanetPosition *p) {
-  fprintf(out, "%5.1f%s %s", p->degree_in_sign, "\xc2\xb0", astro_sign_name(p->sign));
+  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);
 }
 
 void reading_print_text(const DailyReading *r, FILE *out) {
@@ -68,8 +69,8 @@ void reading_print_text(const DailyReading *r, FILE *out) {
 }
 
 static void print_body_row_html(FILE *out, const char *label, const PlanetPosition *p) {
-  fprintf(out, "<tr><td>%s</td><td>%.1f&deg; %s</td></tr>\n", label,
-          p->degree_in_sign, astro_sign_name(p->sign));
+  fprintf(out, "<tr><td>%s</td><td>%.1f&deg; %s</td><td>%s %d</td></tr>\n", label,
+          p->degree_in_sign, astro_sign_name(p->sign), ui("ui.house", "House"), p->house);
 }
 
 void reading_print_html(const DailyReading *r, FILE *out) {

engine/tests/smoke_test.c

@@ -52,6 +52,14 @@ static void test_natal_sun_sign(void) {
   astro_compute_natal_chart(&birth, &chart);
 
   assert(chart.bodies[PLANET_SUN].sign == SIGN_GEMINI);
+
+  /* Whole-sign house invariant: body.house (1-12) must name the house
+   * whose sign (chart.houses[house-1]) is that same body's sign. */
+  for (int b = 0; b < NUM_BODIES; b++) {
+    assert(chart.bodies[b].house >= 1 && chart.bodies[b].house <= 12);
+    assert(chart.houses[chart.bodies[b].house - 1] == chart.bodies[b].sign);
+  }
+
   printf("PASS test_natal_sun_sign\n");
 }
 
@@ -74,6 +82,12 @@ static void test_reading_generate_smoke(void) {
   for (int b = 0; b < NUM_BODIES; b++) {
     assert(r1.natal.bodies[b].ecliptic_longitude == r2.natal.bodies[b].ecliptic_longitude);
     assert(r1.transits.bodies[b].ecliptic_longitude == r2.transits.bodies[b].ecliptic_longitude);
+
+    /* Transiting planets' houses are read against the natal chart's
+     * houses, not a fresh chart for "now" - same invariant as the natal
+     * bodies, but checked against r1.natal.houses. */
+    assert(r1.transits.bodies[b].house >= 1 && r1.transits.bodies[b].house <= 12);
+    assert(r1.natal.houses[r1.transits.bodies[b].house - 1] == r1.transits.bodies[b].sign);
   }
   assert(r1.transits.aspect_count == r2.transits.aspect_count);