Unify quickstart: bring up complete stack (frontend + backend + database) in one command

- Add frontend service to docker-compose.yml (port 4200)
- Simplify quickstart scripts to start all services together
- Remove need for separate dev-start scripts and proxy config
- Frontend now accessible at http://localhost:4200 with nginx proxying API requests

docker-compose.yml

@@ -57,8 +57,20 @@ services:
       timeout: 10s
       retries: 3
 
-# Frontend service removed from default compose - use dev-start.sh for development
-# For production with built frontend, use: docker-compose -f docker-compose.production.yml up
+  frontend:
+    build:
+      context: .
+      dockerfile: Dockerfile.frontend
+    ports:
+      - "4200:80"
+    depends_on:
+      api:
+        condition: service_healthy
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:80"]
+      interval: 30s
+      timeout: 10s
+      retries: 3
 
 volumes:
   postgres_data: