Fix: Add trust proxy setting for Caddy reverse proxy

- Added app.set('trust proxy', true) to backend configuration
- Resolves rate limiting errors when behind Caddy reverse proxy
- Fixes document upload failures caused by X-Forwarded-For header issues

backend/src/index.ts

@@ -23,6 +23,9 @@ dotenv.config();
 const app = express();
 const PORT = process.env.PORT || 3001;
 
+// Trust proxy when behind reverse proxy (Caddy)
+app.set('trust proxy', true);
+
 // Initialize Prisma client
 export const prisma = new PrismaClient({
   log: ['query', 'info', 'warn', 'error'],