fix: Add missing health check endpoint

[Hell1213]

Implements /health endpoint for Docker health checks and monitoring. Fixes missing health endpoint referenced in docker-compose.yml.

Description

Adds missing /health endpoint that was referenced in docker-compose.yml but not implemented. Docker health checks were failing with 404 errors, preventing proper container monitoring and orchestration.

• Fixes: Missing /health endpoint causes Docker health checks to fail #296

Checklist

• Ran npx prettier --write . (for formatting)
• Ran gofmt -w . (for Go backend)
• Ran npm test (for JS/TS testing)
• Added unit tests, if applicable
• Verified all tests pass
• Updated documentation, if needed

Additional Notes

Created backend/controllers/health.go with proper JSON response and method validation. Added comprehensive tests in backend/controllers/health_test.go covering both success and error cases. Registered endpoint in main.go without rate limiting as health checks need fast response times.

[github-actions]

Thank you for opening this PR!

Before a maintainer takes a look, it would be really helpful if you could walk through your changes using GitHub's review tools.

Please take a moment to:

• Check the "Files changed" tab
• Leave comments on any lines for functions, comments, etc. that are important, non-obvious, or may need attention
• Clarify decisions you made or areas you might be unsure about and/or any future updates being considered.
• Finally, submit all the comments!

More information on how to conduct a self review:
https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/reviewing-proposed-changes-in-a-pull-request

This helps make the review process smoother and gives us a clearer understanding of your thought process.

Once you've added your self-review, we'll continue from our side. Thank you!

[Hell1213]

Fixed Docker health check failures by implementing the missing /health endpoint. Added proper handler with JSON response and comprehensive test coverage.

The implementation addresses the core issue - Docker containers can now properly monitor backend health status instead of getting 404 errors.

[Hell1213]

@its-me-abhishek ,PR is ready plss have a look at implementation .
Thanks

[its-me-abhishek]

Please rename this file, functions to HealthCheck instead of just Health