Update default port to 3005 for test instance

backend/server.ts

@@ -468,8 +468,8 @@ app.onError((err, c) => {
   return c.text('Internal Server Error', 500);
 });
 
-// Default to 3004 for Redis branch; can be overridden by Environment=PORT
-const PORT = Number(process.env.PORT || 3004);
+// Default to 3005 for test instance; can be overridden by Environment=PORT
+const PORT = Number(process.env.PORT || 3005);
 
 logLine('logs/server.log', `Starting frontend server (Redis version) on port ${PORT}`);