Add /hello endpoint returning plain-text greeting

[Copilot]

The issue requested support for a simple hello response. This change adds a dedicated route so clients can retrieve that exact greeting directly.

• API surface

  • Added a new GET /hello endpoint in index.js.

• Response behavior

  • Returns plain text: hello.

• Implementation

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