[backend][logging] Add structured LoggingInterceptor with pino

[mc-stephen]

Summary

Adds a structured LoggingInterceptor that emits one structured log line per request using pino.

Changes

• New: src/common/interceptors/logging.interceptor.ts — NestJS interceptor that logs method, path, status, duration_ms, user_id, and request_id per request
• Modified: src/main.ts — registers the interceptor globally via app.useGlobalInterceptors()
• Modified: package.json — added pino dependency

Acceptance Criteria

• LoggingInterceptor emits one structured log per request: method, path, status, duration_ms, user_id, request_id
• Uses pino as the underlying logger
• Log lines parse as level=info fields=...

Closes #523

[Xhristin3]

Solid logging interceptor @mc-stephen, exactly the kind of structured-logging we want — merging 🚀

[Xhristin3]

@mc-stephen — quick follow-up: tried to merge but there are real merge conflicts against main now (other PRs landed first). Could you rebase onto main and I'll merge on the next push. 🙏

[mc-stephen]

Solid logging interceptor @mc-stephen, exactly the kind of structured-logging we want — merging 🚀

Thanks.

Conflict fixed, accepted both releases, coming and current.
nothing breaks.