docs : add JSDoc documentation to lib/request-id.ts

[tmdeveloper007]

Summary of What Needs to be Done

Add JSDoc documentation to lib/request-id.ts. The file exports getRequestId but lacks any JSDoc comments explaining its behavior, return type, or edge cases.

Changes that Need to be Made

1. Add a module-level JSDoc comment.
2. Add @function JSDoc for getRequestId with @returns, @throws (if applicable), and @example.
3. Document the behavior when x-request-id header is absent.

Impact that it would Provide

• Improves developer understanding of how request tracing works in the app.
• Makes the function's contract explicit for future maintainers.
• Follows the established documentation standards in the codebase.

Note

Please assign this issue to the tmdeveloper007 account.

[AI-Explorer786]

/assign