feat : add health check endpoint for backend server

[tmdeveloper007]

Summary of What Needs to be Done

The backend server currently has no health check endpoint. A /health route should be added to allow monitoring tools, load balancers, and DevOps tooling to verify the server is running and responsive.

Changes that Need to be Made

1. Create a new route file backend/routes/healthRoutes.js (or add to an existing file):
   • Add a GET /health route at backend/routes/healthRoutes.js
   • The handler should return a JSON response: { status: 'ok', timestamp: <ISO timestamp> }
   • Use HTTP 200 OK
2. Mount the route in backend/src/server.js (or the main entry):
   • Import and mount the health routes at /health path

Impact that it would Provide

• Enables uptime monitoring tools to check server health
• Allows load balancers to verify backend is reachable
• Provides a simple diagnostics endpoint for debugging

Note: Please assign this issue to the tmdeveloper007 account.