* fix(runtime): reclaim idle keyed locks safely
Replace the per-loop thread lock registries with a waiter-aware keyed lock table. Count holders and queued waiters before acquisition so idle entries can be reclaimed without allowing a late caller to bypass an existing waiter.
Add regression coverage for runtime call-site reclamation, goal/checkpoint domain independence, queued-waiter ordering, cancellation cleanup, high-cardinality key reclamation, and cross-event-loop isolation.
Fixes#5171
* style(runtime): format keyed lock helper
