Extend B4 (#28) browser_metrics.
Scope
- Expose live circuit-breaker state per host (open/half-open/closed + cooldown remaining), read from the B2 breaker map (needs a read accessor;
breaker.ts is at the 100-line cap → split first).
- Latency percentiles (p50/p95) via a small bounded sample buffer (currently only avg/min/max).
- Optional per-minute rate (requestsFinishedPerMinute style).
Acceptance
browser_metrics returns breakerHosts: [{ origin, state, retryInMs }] and p95DurationMs.- No new dependency; counters stay process-global.
Priority — medium; pure observability, low risk.
Extend B4 (#28)
browser_metrics.Scope
breaker.tsis at the 100-line cap → split first).Acceptance
browser_metricsreturnsbreakerHosts: [{ origin, state, retryInMs }]andp95DurationMs.Priority — medium; pure observability, low risk.