Add daily notification wakeups and a make watchapp packaging target

Schedules a one-shot Pebble wakeup for the configured notification
time, re-arming it on every launch and config change, and vibrates/
refreshes the report when it fires (foreground or fresh launch).
Also adds a `make watchapp` target that builds the watchapp via the
Pebble SDK and copies a versioned .pbw to dist/, matching `make
package`'s version resolution — deliberately not wired into CI, which
has no Pebble SDK installed.

Makefile

@@ -87,7 +87,12 @@ GUIDANCE_TEST_BIN     := $(BUILD_DIR)/guidance_test
 ARCH        := $(shell uname -m)
 PACKAGE_DIR := $(BUILD_DIR)/package
 
-.PHONY: all test clean images i18n scripts package
+# ---- watch app (Pebble) ----
+
+WATCH_DIR := watch
+WATCH_PBW := $(WATCH_DIR)/build/watch.pbw
+
+.PHONY: all test clean images i18n scripts package watchapp
 
 all: $(ENGINE_BINARY) $(INTERP_BINARY) images i18n scripts
 
@@ -208,3 +213,32 @@ clean:
 	rm -rf $(BUILD_DIR) $(ENGINE_BINARY) $(INTERP_BINARY) $(DIST_IMG_DIR) $(DIST_I18N_DIR) \
 		$(DIST_DIR)/run-engine.sh $(DIST_DIR)/run-interpreter.sh
 	# user.properties holds the user's own data - never removed by clean.
+
+# Builds the Pebble watchapp (`pebble build` in watch/, via its own
+# wscript/pebble_sdk waf tooling - not a plain C toolchain, so this is a
+# separate target from `all` rather than one of its prerequisites) and
+# copies the resulting .pbw into dist/, versioned the same way `package`
+# above versions the CLI tarball (current git tag, or
+# `make watchapp VERSION=1.2.3` to override). Requires the Pebble SDK
+# (`pebble` on PATH, plus Python 3 + Pillow for watch/scripts/*.py - see
+# watch/wscript) - this is NOT checked by the root `make`/`make test`,
+# so a machine without the Pebble SDK can still build/test the CLI.
+watchapp:
+	cd $(WATCH_DIR) && pebble build
+	@mkdir -p $(DIST_DIR)
+	@V="$(VERSION)"; \
+	if [ -z "$$V" ]; then \
+		if TAG=$$(git describe --tags --exact-match --match 'v[0-9]*.[0-9]*.[0-9]*' 2>/dev/null); then \
+			V=$${TAG#v}; \
+		else \
+			V="0.0.0-dev+$$(git rev-parse --short HEAD)"; \
+			echo "WARNING: HEAD is not on a vX.Y.Z tag - building placeholder version $$V (push a tag to drive a real release version)" >&2; \
+		fi; \
+	fi; \
+	case "$$V" in \
+		[0-9]*.[0-9]*.[0-9]*) ;; \
+		*) echo "PREFLIGHT FAIL: VERSION '$$V' is not a semantic version (expected X.Y.Z, optionally with a -pre+meta suffix)" >&2; exit 1;; \
+	esac; \
+	PBW_NAME="deck-in-a-dash-$$V.pbw"; \
+	cp $(WATCH_PBW) "$(DIST_DIR)/$$PBW_NAME"; \
+	echo "Wrote $(DIST_DIR)/$$PBW_NAME"