Add Cloudflare/nginx proxy support and production setup

- Updated ProxyFix configuration for Cloudflare + nginx
- Added custom IP detection for real client IPs
- Updated rate limiting to use real IPs
- Added nginx configuration example
- Added Cloudflare setup guide
- Added production server setup script

config.json

@@ -17,6 +17,12 @@
     "session_cookie_secure": false,
     "session_cookie_httponly": true,
     "session_cookie_samesite": "Lax",
+    "proxy_setup": {
+      "behind_cloudflare": true,
+      "behind_nginx": true,
+      "trusted_proxies": 2,
+      "cloudflare_ip_header": "CF-Connecting-IP"
+    },
     "security_headers": {
       "x_content_type_options": "nosniff",
       "x_frame_options": "DENY",