Add GET /hello endpoint returning plain text greeting

[Copilot]

The issue requested a minimal implementation for a hello response. This PR adds a dedicated route that serves hello without altering existing routes or page behavior.

• API change

  • Added GET /hello to the Express app in index.js.
  • Response is plain text: hello.

• Scope

  • No changes to existing /, /silly, /silly2, PATCH /, or /test handlers.
  • Change is isolated to route registration in the main server file.

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