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

frontend/nginx.conf

@@ -0,0 +1,19 @@
+server {
+    listen 80;
+    server_name localhost;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+
+    location /api/ {
+        proxy_pass http://backend:8000;
+        proxy_http_version 1.1;
+        proxy_set_header Upgrade $http_upgrade;
+        proxy_set_header Connection 'upgrade';
+        proxy_set_header Host $host;
+        proxy_cache_bypass $http_upgrade;
+    }
+}