Update server listen port to 7823

[Copilot]

This change updates the application’s runtime port from 1245 to 7823, aligning the server with the required port configuration. No routing or handler behavior was modified.

• Port configuration
  • Updated the server port constant in index.js from 1245 to 7823.
  • Kept all references tied to the same port variable, so startup logs and rendered status output remain consistent with the active listener.

const port = 7823;
app.listen(port, () => console.log(`Example app listening on port ${port}!`));