Add React frontend to Docker Compose

- Created frontend/Dockerfile with multi-stage build for optimized production bundle
- Created frontend/.dockerignore to exclude node_modules and build artifacts
- Added frontend service to docker-compose.yml with:
  - Auto-build from frontend/Dockerfile
  - Port 3000 mapping
  - Health checks (wget to http://localhost:3000)
  - Dependency on healthy Kafka and Redis
  - Production environment (NODE_ENV=production)
  - Auto-restart on failure
  - Proper network connectivity
- Created DOCKER_QUICK_START.md with simplified setup guide:
  - Single docker compose up starts infrastructure + frontend
  - Cleaner workflow (2-3 terminals instead of 4)
  - Production-like testing (not dev mode)
  - Complete troubleshooting section
- Updated FULLSTACK_GUIDE.md to highlight Docker-integrated frontend
- Frontend now runs as optimized 63KB gzip production build in Docker

All components now start together:
  docker compose up      # Infrastructure + React frontend (Docker)
  uvicorn api.main:app   # API (your terminal)
  python pipeline.py     # Consumer (your terminal)

Access frontend at: http://localhost:3000

Co-authored-by: Copilot <[email protected]>

frontend/.dockerignore

@@ -0,0 +1,10 @@
+node_modules
+npm-debug.log
+dist
+.git
+.gitignore
+README.md
+.DS_Store
+.vscode
+.idea
+*.local