docs(unified-session): update class docstring (no more circuit breaker)

PR #393 review (Copilot): the class-level JSDoc still listed "Circuit
breaker protection" as a feature, but the protection was removed in
commit b531b46999 in favour of best-effort single-attempt semantics
(telemetry is non-critical — failures are swallowed and counted in the
hookFailures metric).

Updated the bullet point to describe what actually happens now.

Note: not addressing the breaking-API change comments (removed
enableCircuitBreaker option from UnifiedSessionOptions, removed
circuitBreakers/getCircuitBreakerStats/resetCircuitBreakers from
makeSocket() return, removed circuit_breaker_* Prometheus metrics)
per maintainer policy — this fork has a single consumer (zpro.io),
downstream forks absorb on merge.

src/Utils/unified-session.ts

@@ -90,7 +90,9 @@ export type UnifiedSessionTrigger = 'login' | 'pairing' | 'presence' | 'manual'
  * Manages the unified_session telemetry feature with:
  * - Server time synchronization
  * - Rate limiting (prevents spam)
- * - Circuit breaker protection
+ * - Best-effort send semantics (failures are swallowed and counted —
+ *   telemetry is non-critical so a single attempt with the underlying
+ *   sendNode timeout is enough; no retry, no circuit breaker)
  * - Prometheus metrics integration
  * - Structured logging
  *