Fix core-hub stabilization evidence sink posting

Allow persist_ops_evidence to emit State Hub progress for core-hub context
sources so scheduled stabilization checks record hub-visible evidence.

tests/test_ops_evidence_sinks.py

@@ -136,6 +136,57 @@ def test_state_hub_progress_sink_posts_compact_probe_summary(monkeypatch) -> Non
     assert "token=secret" not in serialized
 
 
+def test_core_hub_stabilization_sink_posts_progress(monkeypatch) -> None:
+    posts: list[dict[str, Any]] = []
+
+    def fake_get(url: str, **kwargs: Any) -> DummyResponse:
+        return DummyResponse([])
+
+    def fake_post(url: str, **kwargs: Any) -> DummyResponse:
+        posts.append({"url": url, **kwargs})
+        return DummyResponse({"id": "progress-core-hub-1"})
+
+    monkeypatch.setattr(httpx, "get", fake_get)
+    monkeypatch.setattr(httpx, "post", fake_post)
+
+    result = persist_ops_inventory_evidence(
+        {
+            "activity_id": "activity-core-hub",
+            "run_id": "12345678-aaaa-bbbb-cccc-123456789abc",
+            "scheduled_for": "2026-07-07T10:15:00+00:00",
+            "version_used": 1,
+            "context_sources": [
+                {
+                    "type": "core-hub",
+                    "query": "stabilization_check",
+                    "bind_to": "context.core_hub_stabilization_check",
+                    "params": {
+                        "evidence_sinks": [
+                            {
+                                "type": "state-hub-progress",
+                                "event_type": "core_hub_stabilization_check",
+                                "state_hub_url": "http://state-hub.test",
+                            }
+                        ]
+                    },
+                }
+            ],
+            "context": {
+                "core_hub_stabilization_check": {
+                    "kind": "core_hub_stabilization",
+                    "overall_pass": True,
+                    "checks": {"widget_types_count": {"pass": True, "count": 26}},
+                }
+            },
+        }
+    )
+
+    assert result[0]["status"] == "posted"
+    body = posts[0]["json"]
+    assert body["event_type"] == "core_hub_stabilization_check"
+    assert "Core Hub stabilization" in body["summary"]
+
+
 def test_state_hub_progress_sink_is_idempotent(monkeypatch) -> None:
     idempotency_key = f"{_run_id()}:ops_probe:ops_inventory_probe"