[Epic] Logging subsystem hardening (FD leak/rotation/TS conversion)

Tracking epic for logging-infrastructure hardening: log-rotator FD leak/retention, cache-hit/outgoing-request correlation logging, stderr routing, scoped-logger naming, and the JS→TS conversion of the logger module.

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_Filed by Claude (Opus 4.8), issue-backlog triage & grouping pass._

This is an epic covering log-rotator FD leak and retention, correlation logging, stderr routing, scoped-logger naming, and JS-to-TS conversion. Start by breaking the listed work into focused tasks and locating the logging subsystem and logger module; done means each concern has a defined change and the logger conversion is complete.

Written by the indexing model from the issue text.