* fix(credential-pool): throttle "no available entries" log to stop Windows log-lock storm
Credential selection runs on a hot path (every model call plus auxiliary
tasks), so an empty/exhausted pool logged "no available entries" at INFO on
*every* selection. On Windows, where multiple Hermes processes share one
rotating log guarded by concurrent-log-handler's cross-process lock, that
per-selection volume storms the lock (RuntimeError: Cannot acquire lock after
20 attempts), pegs a core, and stalls the asyncio event loop long enough that
the Desktop backend readiness probe times out ("Timed out connecting to Hermes
backend after 15000ms") even though the backend already announced
HERMES_BACKEND_READY.
Log the condition at most once per 60s window, re-arming on a successful
selection so recovery->re-exhaustion still surfaces promptly. Same fix class as
the warn-once dedup in #58265.
* test(credential-pool): cover no-available-entries log throttle
Assert the empty-pool INFO line logs at most once per throttle window, logs
again after the window elapses, and re-arms on a successful selection so a
recover->re-exhaust transition surfaces promptly. Uses a deterministic fake
monotonic clock (no sleeps, no network).
HexLab
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