Improve server/index.js: better error handling, security, config

[gssi962]

🚀 Pull Request

Description

This PR improves the server/index.js file by making the backend more secure, flexible, and easier to maintain.

Related Issue

Closes #48

Type of Change

This PR is an enhancement ⚡ to the backend. It improves server/index.js by adding configurable CORS, a 404 route handler, a better error handler, enhanced /api/health endpoint, security middlewares (helmet and rate-limit), and request logging (morgan). No bug fixes or documentation updates are included in this PR.

How Has This Been Tested?

Tested locally on server

Verified /api/health returns DB status and uptime

Tested unknown routes return 404 JSON

Verified CORS works with .env configuration

Checked logging via morgan

Verified server starts without errors

Screenshots (if applicable)

N/A – backend changes only

Checklist

• [YES ] I followed the Contributing Guide
• [YES ] My code follows the project’s style guidelines
• [ YES] I performed a self-review of my code
• [YES ] I updated documentation where necessary
• [ YES] My changes generate no new warnings

[gssi962]

I have created a pull request for issue #48. Kindly review it.

[DeadIndian]

✅

[gssi962]

I have one request. Kindly update my score of GSSOC and OSCI as today is the last date of contribution of OSCI.