Add production deployment config, Alembic migration, switch to Haiku

- Production Docker Compose with Caddy reverse proxy, Gunicorn, Nginx
- Multi-stage frontend build for production
- Deploy script and automated database backup script
- Initial Alembic migration with all tables
- Switch recommendation model from Sonnet to Haiku for cost efficiency

frontend/nginx.conf

@@ -0,0 +1,14 @@
+server {
+    listen 80;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+
+    location /assets/ {
+        expires 1y;
+        add_header Cache-Control "public, immutable";
+    }
+}