Create API documentation with Swagger/OpenAPI

[yashdev9274]

Description

Document the API endpoints using Swagger/OpenAPI specification.

Expected Deliverables

• Set up swagger-jsdoc and swagger-ui-express
• Document all existing API routes
• Add request/response schemas
• Include authentication requirements
• Create /api/docs endpoint for interactive documentation

Areas to Consider

• Use JSDoc comments for route descriptions
• Define reusable schemas
• Group endpoints by functionality