feat(deploy): gate claims on pinned runtime readiness

Assistant: codex
Assistant-Model: gpt-5.6-sol
Assistant-Session: 01a06ba0-10aa-7ea0-b20a-4f3fac39efe9

rein_aharness/claim_loop.py

@@ -798,6 +798,15 @@ def run_claim_loop(
     signal.signal(signal.SIGTERM, _handle_sig)
 
     client = ActivityCoreOpsClient()
+    from rein_aharness.readiness import run_readiness_checks
+
+    readiness = run_readiness_checks(client)
+    if not readiness.ok:
+        failed = ", ".join(
+            check.name for check in readiness.checks if not check.ok
+        )
+        logger.error("claim-loop readiness failed: %s", failed)
+        return 2
     logger.info(
         "claim-loop start worker_id=%s url=%s labels=%s interval=%ss once=%s",
         client.config.worker_id,