feat(logger): add pluggable error sink

[karagozemin]

Summary

• add exported setErrorSink and clearErrorSink APIs for warn/error telemetry
• keep default guarded console behavior unchanged when no sink is registered
• wrap sink calls so telemetry failures cannot throw, and document the PII-safe sink contract
• cover no-sink, clear, throwing-sink, warn/error, production sink, and metadata-only cases in logger tests

Closes #279

Security

• sink TSDoc and README documentation forbid forwarding JWTs, credentials, full user profiles, email addresses, or other PII
• tests verify the sink receives only the explicit message and metadata passed to the logger

Verification

• npm run test -- src/shared/utils/logger.test.ts 15 tests passed
• npx eslint src/shared/utils/logger.ts src/shared/utils/logger.test.ts
• npm run typecheck
• npm run build

[Jagadeeshftw]

hey @karagozemin, thanks for jumping in! closing this pr because the author needs to be assigned to the linked issue (#279) before opening a pr. please comment on the issue requesting assignment, wait to be assigned, then re-raise your pr. this keeps work fairly distributed across contributors. hope to see a revised pr from you soon!