feat(api): add Swagger documentation and basic API endpoints

[mukeshdhadhariya]

PR: Add Swagger docs + health, register, and login endpoints

Summary

This PR integrates Swagger (OpenAPI) documentation into the project and implements three basic API endpoints: /health, /register, and /login. The goal is to provide an interactive, discoverable API reference for developers and contributors and to make it easy to explore and test endpoints.

Changes included

• Integrated swagger-jsdoc and swagger-ui-express to serve OpenAPI docs.
• Added Swagger/OpenAPI documentation for the following endpoints:
  • GET /health — simple health check endpoint.
  • POST /api/auth/register — user registration (request body + responses documented).
  • POST /api/auth/login — user login (request body + success and error responses documented).
• Added JSDoc (@openapi) comments above controllers/routes so swagger-jsdoc can auto-generate the spec.
• Configured src/utils/swagger.js to scan routes and controllers and to expose the OpenAPI definition.
• Mounted Swagger UI at /api-docs for interactive documentation and testing.
• Added generation script to produce swagger.json for CI/CD / client generation.

Endpoints (short reference)

GET /health

Returns API health status. 200 with JSON response like { "message": "API is working", "status": 200 }.

POST /api/auth/register

Registers a new user. Request body:

{
  "username": "string",
  "email": "string",
  "fullname": "string",
  "password": "string",
  "role": "optional role id"
}

Responses: 201 (created), 400 (validation/duplicate), 500 (server error).

POST /api/auth/login

Authenticates a user and returns JWT + refresh token. Request body:

{
  "email": "string",
  "password": "string"
}

Responses: 200 (success with token and refreshToken), 400 (missing fields), 401 (invalid credentials).

/api-docs can see all docs

[mukeshdhadhariya]

@Somilg11 review , and i fix this issue #21(hard) and add register route(medium)

[mukeshdhadhariya]

@Somilg11 review and merge , all swagger end points done with no conflicts
updated