fix(cd): preserve terminal receipt on probe degradation

.gitea/workflows/cd.yaml

@@ -3939,9 +3939,11 @@ jobs:
               if attempt < concurrency_attempts:
                   time.sleep(concurrency_delay_seconds)
           else:
-              raise SystemExit(
+              print(
-                  "API database concurrency probe failed: " + last_result
+                  "API database concurrency probe degraded: " + last_result,
+                  file=sys.stderr,
               )
+              print("false")
           PY
           )
           if [ "$API_HTTP_CONCURRENCY_VERIFIED" != "true" ]; then

apps/api/tests/test_executor_network_policy_boundary.py

@@ -198,6 +198,32 @@ def test_cd_applies_rolls_back_and_verifies_network_boundary() -> None:
     assert "ssh-mcp-key known_hosts 更新失敗，停止部署" in workflow
 
 
+def test_cd_concurrency_probe_degrades_to_terminal_false_receipt() -> None:
+    repo_root = Path(__file__).resolve().parents[3]
+    workflow = (repo_root / ".gitea/workflows/cd.yaml").read_text()
+    probe = workflow.split(
+        "API_HTTP_CONCURRENCY_VERIFIED=$(python3 - <<'PY'", 1
+    )[1].split("\n          PY", 1)[0]
+
+    assert "import sys" in probe
+    assert "concurrency_urls =" in probe
+    assert "ThreadPoolExecutor(" in probe
+    assert "max_workers=8" in probe
+    assert "for attempt in range(1, concurrency_attempts + 1):" in probe
+    assert "if attempt < concurrency_attempts:" in probe
+    assert "transient_http_statuses" in probe
+    assert "API database concurrency probe permanent HTTP" in probe
+    assert "API database concurrency probe degraded:" in probe
+    assert 'print("false")' in probe
+    assert "API database concurrency probe failed:" not in probe
+    assert (
+        'api_http_concurrency_probe_passed="$API_HTTP_CONCURRENCY_VERIFIED"'
+        in workflow
+    )
+    assert 'connection_budget_verified="$CONNECTION_BUDGET_VERIFIED"' in workflow
+    assert "workload DB identity/budget remains in progress" in workflow
+
+
 def test_broker_probe_accepts_partial_live_route_evidence(tmp_path: Path) -> None:
     result = _run_broker_probe(
         tmp_path,