feat: complete mealplanner app (backend + frontend + deployment)

.NET 8 backend with Zitadel JWT auth, TheMealDB integration,
weekly meal plan generation, shopping list aggregation.
Vue 3 + Tailwind 4 frontend with dark emerald theme,
manual OIDC PKCE auth, all views implemented.
Multi-stage Dockerfile with nginx reverse proxy.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker-compose.yml

@@ -0,0 +1,13 @@
+version: '3.8'
+services:
+  app:
+    build: .
+    ports:
+      - "3000:80"
+    environment:
+      - ConnectionStrings__DefaultConnection=Host=host.docker.internal;Port=54320;Database=mealplanner;Username=mika;Password=${SHARED_POSTGRES_PASSWORD}
+      - Zitadel__Issuer=https://auth.kuns.dev
+      - Zitadel__ClientId=${ZITADEL_CLIENT_ID}
+      - AllowedOrigin=http://localhost:3000
+      - ASPNETCORE_URLS=http://+:5000
+      - ASPNETCORE_ENVIRONMENT=Production