docs(swagger-api): add swagger api documentation

[anuragShingare30]

Pull Request

Description

• Added Swagger UI documentation at /api-docs route
• Created /docs directory with API definitions separated from controllers/routes
• Added npm run generate:swagger script to generate documentation locally
• Configured environment-based docs availability (development only by default)
• Generated files excluded from version control
• Enables developers to browse and test API endpoints interactively

Fixes #9

Type of Change

• New feature (non-breaking change which adds functionality)
• Documentation update
• Dependency update
• Test addition / improvement

Checklist

Code Quality

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

Testing

• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have tested the API endpoints manually (if applicable)
• I have tested with different data scenarios

Security

• I have checked for security vulnerabilities in my code
• I have not hardcoded sensitive information
• Input validation is properly implemented
• I have not introduced any new dependencies without review

Performance

• I have considered the performance impact of my changes
• I have optimized database queries (if applicable)
• I have not introduced memory leaks
• Performance-critical code has been profiled

Testing Evidence

1. Start the server locally at port 3000: `npm run dev`
2. Generate documentation locally: `npm run generate:swagger`
3. Access the docs locally at: `http://localhost:3000/api-docs`

Additional Notes

• I have not change the README.md file. If needed will add the necessary steps and guide.

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Checklist for Reviewers:

• Code follows project style guidelines
• Changes are well-documented
• Tests are adequate
• No breaking changes (or breaking change is intentional)
• Database migrations are safe
• Performance impact is acceptable
• Security concerns are addressed