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/app/api/pantry.py

@@ -0,0 +1,20 @@
+from fastapi import APIRouter, Depends
+from sqlalchemy.orm import Session
+from app.database import get_db
+
+router = APIRouter()
+
+
+@router.get("/")
+def get_pantry(db: Session = Depends(get_db)):
+    return {"message": "Pantry endpoint - not yet implemented"}
+
+
+@router.post("/")
+def add_pantry_item(db: Session = Depends(get_db)):
+    return {"message": "Add pantry item - not yet implemented"}
+
+
+@router.delete("/{item_id}")
+def remove_pantry_item(item_id: str, db: Session = Depends(get_db)):
+    return {"message": f"Remove pantry item {item_id} - not yet implemented"}