refactor/rfc-006-worker-runtime
main
1. trySendSync: wrap child.send in try/catch — IPC race between connected check and send 2. gracefulStop: same try/catch for shutdown send 3. Remove crashTimestamps reset on ready — crash window detection was being bypassed
- Add trySendSync() for synchronous send when worker is ready+connected - sendCompute uses sync path first, async fallback for cold start - Add forwardStderr, allowRespawn, hasDisconnectedChild, onReady(key,msg) - Tests: add connected:true to mocks, flush async fork microtasks - All 167 daemon tests pass
RFC-006 Phase 1: ManagedWorker state machine + WorkerRuntime<K> with cold start, crash respawn, drain/evict, graceful shutdown. 8 test cases covering all lifecycle scenarios.