Add GET /hello endpoint returning plain text response

[Copilot]

The issue required supporting a simple hello behavior in the server. This change adds a dedicated endpoint that returns the expected plain-text payload.

• Endpoint addition

  • Introduced a new GET /hello route in the Express app.
  • Route returns a literal "hello" response body.

• Behavioral scope

  • Existing routes and handler wiring remain unchanged.
  • Change is isolated to index.js route definitions.

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