fix: increase Node keepAliveTimeout behind reverse proxies to prevent 502s

- Set server.keepAliveTimeout to 185s to safely outlive default Traefik/AWS ALB idle timeouts (typically 60-180s)
- Resolves random "Failed to fetch" edge cases caused by Node.js's notoriously short 5s default timeout
Closes #3008

server/src/index.ts

@@ -542,6 +542,12 @@ export async function startServer(): Promise<StartedServer> {
     resolveSession,
   });
   const server = createServer(app as unknown as Parameters<typeof createServer>[0]);
+
+  // Increase keep-alive timeouts to safely outlive default idle timeouts
+  // of common reverse proxies and load balancers (like AWS ALB, Nginx, or Traefik).
+  // This prevents intermittent 502/ECONNRESET errors caused by Node's 5s default.
+  server.keepAliveTimeout = 185000;
+  server.headersTimeout = 186000;
   
   if (listenPort !== config.port) {
     logger.warn(`Requested port is busy; using next free port (requestedPort=${config.port}, selectedPort=${listenPort})`);