test(resilience): 34 tests for preflight/classifier/backoff/breaker (ORCH-1)

Covers preflight FAIL->queued + cache, transient/permanent classifier +
Retry-After, exp backoff + available_at gating, launcher transient vs permanent
finalize, circuit breaker open/half-open/closed. test_queue worker tests stub
preflight OK. Popen never spawned.

tests/test_queue.py

@@ -236,6 +236,12 @@ class TestObservability:
 # QueueWorker max_concurrency (launch_job fully mocked — no real Popen)
 # ---------------------------------------------------------------------------
 class TestWorkerConcurrency:
+    @pytest.fixture(autouse=True)
+    def _ok_preflight(self, monkeypatch):
+        # ORCH-1 resilience: the worker gates claims behind preflight; in tests there
+        # is no claude binary, so stub preflight OK to exercise pure queue/concurrency.
+        monkeypatch.setattr("src.queue_worker.preflight.check", lambda *a, **k: (True, "ok"))
+
     def test_worker_respects_max_concurrency(self, monkeypatch):
         from src.queue_worker import QueueWorker