feat: add Request Interceptor and request ID generation utilities (#2176)

[nagi1]

This pull request introduces infrastructure for request ID tracing to improve request correlation and observability. It adds a configurable request ID header, generates or propagates request IDs, and ensures the request ID is included in responses. The changes also include comprehensive tests for these features.

Request ID tracing and propagation:

• Added a new module src/nestjs/requestId.ts providing:

  • generateRequestId for extracting or generating a request ID (UUID v4) from incoming requests, using a configurable header (WAHA_REQUEST_ID_HEADER, defaulting to x-request-id).
  • RequestIdInterceptor, a NestJS interceptor that writes the request ID to the response header, matching the incoming header name.
  • getRequestIdHeader utility for retrieving the configured header name.

• Integrated request ID tracing into the core app:

  • Registered RequestIdInterceptor as a global interceptor in PROVIDERS_BASE to ensure all responses include the request ID header.
  • Configured pino-http logging to use generateRequestId, ensuring consistent request ID usage in logs and tracing.
  • Imported the new tracing utilities into the core module.

Testing and reliability:

• Added a comprehensive test suite in src/nestjs/requestId.test.ts covering:
  • Header configuration and environment variable overrides.
  • Request ID extraction, generation, and propagation logic.
  • Behavior of the RequestIdInterceptor under various scenarios, including custom headers and edge cases.

[nagi1]

Related issue: #2176

[nagi1]

@devlikepro Kind Reminder to review and merge this!