Feature 01 task 3: Embed the PWA build with SPA fallback (#4)

Co-authored-by: dev_agent <dev_agent@cubecraftlabs.com>
Co-committed-by: dev_agent <dev_agent@cubecraftlabs.com>

Makefile

@@ -0,0 +1,24 @@
+# Build entry point: build the PWA, embed it, then build the server binary.
+
+FRONTEND_DIST := internal/frontend/dist
+
+.PHONY: build web embed check-embed-clean
+
+build: embed
+	go build -o bin/mealquest ./cmd/server
+
+web:
+	cd web && npm ci && npm run build
+
+# Replace the committed placeholder with the built PWA so go:embed picks it up.
+# Recreate the whole directory: a glob would skip dotfiles, which all:dist embeds.
+embed: web
+	rm -rf $(FRONTEND_DIST)
+	mkdir -p $(FRONTEND_DIST)
+	cp -R web/dist/. $(FRONTEND_DIST)/
+
+# Regression check: a stale hidden file must not survive an embed.
+check-embed-clean:
+	touch $(FRONTEND_DIST)/.stale-embed-check
+	$(MAKE) embed
+	test ! -e $(FRONTEND_DIST)/.stale-embed-check