Add GET /hi endpoint returning plain-text greeting

[Copilot]

The issue required a minimal implementation for a hi response. This PR adds a dedicated route that serves hi without changing existing endpoint behavior.

• Route addition

  • Added GET /hi to the shared router in patchHandler.js.
  • Response is plain text: hi.

• Behavioral scope

  • No changes to existing /, /test, /silly, /silly2, or PATCH / handlers.
  • Kept the change isolated to one file and one endpoint.

router.get("/hi", (req, res) => {
  console.log(`${new Date()} ${req.method} ${req.path}`);
  res.send("hi");
});