feat: add Phase 1 infrastructure skeleton

Backend (FastAPI):
- docker-compose with all 4 services
- FastAPI app with health endpoints
- SQLAlchemy models for all tables
- Placeholder API endpoints for all routes
- Config and database modules
- requirements.txt with all dependencies

Frontend (React):
- package.json with React, Tailwind, React Query, React Router
- Vite config with API proxy
- Tailwind and TypeScript configs
- Basic App with routing skeleton
- Placeholder pages (Dashboard, MealDetail, Pantry)

Infrastructure:
- nginx config for reverse proxy
- Dockerfile for backend and frontend

backend/requirements.txt

@@ -0,0 +1,16 @@
+fastapi==0.109.0
+uvicorn[standard]==0.27.0
+sqlalchemy==2.0.25
+alembic==1.13.1
+psycopg2-binary==2.9.9
+pydantic==2.5.3
+pydantic-settings==2.1.0
+sendgrid==6.12.0
+playwright==1.41.0
+beautifulsoup4==4.12.3
+lxml==5.1.0
+apscheduler==3.10.4
+python-dotenv==1.0.0
+httpx==0.26.0
+pytest==7.4.4
+pytest-asyncio==0.23.3