fix: serve on port 80 to match Coolify/Traefik routing config

backend/src/index.ts

@@ -22,7 +22,7 @@ import settingsRouter from './routes/settings';
 import notificationsRouter from './routes/notifications';
 
 const app = express();
-const PORT = parseInt(process.env.PORT || '3000', 10);
+const PORT = parseInt(process.env.PORT || '80', 10);
 
 // Trust Coolify/Traefik reverse proxy
 app.set('trust proxy', 1);