feat: Phase 5 stabilization schedules and custodian path URIs

Add phase5_stabilization_check State Hub resolver with progress evidence
sinks, schedule projections for daily and closeout checks, custodian:// and
activity-core:// runtime path resolution, and Railiance mounts under /var/custodian.

tests/test_state_hub_context_resolver.py

@@ -607,3 +607,50 @@ def test_daily_triage_digest_is_curated_scalar_json(monkeypatch) -> None:
         "code_score_high_gain_high_effort_candidates"
     )
     assert digest["ranked_suggestions"][0]["origin_ref"] == "issue-core-ingestion-api-key"
+
+
+def test_phase5_stabilization_check_passes(monkeypatch) -> None:
+    payloads = {
+        "/state/health": {"status": "ok", "db": "connected"},
+        "/state/summary": {
+            "totals": {
+                "workstreams": {"total": 640},
+                "tasks": {"total": 4002},
+                "topics": {"total": 14},
+            }
+        },
+        "/progress/": [],
+    }
+
+    def fake_get(url: str, **kwargs: Any) -> DummyResponse:
+        path = url.replace("http://state-hub.test", "")
+        params = kwargs.get("params") or {}
+        if path == "/progress/":
+            if params.get("event_type") == "consistency_sweep_remote_all":
+                return DummyResponse([
+                    {
+                        "created_at": "2026-07-06T20:00:00+00:00",
+                        "detail": {"exit_code": 0, "skipped_missing": []},
+                    }
+                ])
+            if params.get("event_type") == "daily_triage":
+                return DummyResponse([
+                    {"created_at": "2026-07-06T19:00:00+00:00", "summary": "ok"}
+                ])
+        return DummyResponse(payloads.get(path, {}))
+
+    from datetime import datetime, timezone
+
+    fixed_now = datetime(2026, 7, 7, 10, 0, tzinfo=timezone.utc)
+    monkeypatch.setenv("STATE_HUB_URL", "http://state-hub.test")
+    monkeypatch.setattr(httpx, "get", fake_get)
+    monkeypatch.setattr(
+        "activity_core.context_resolvers.state_hub._utc_now",
+        lambda: fixed_now,
+    )
+
+    result = StateHubContextResolver().resolve("phase5_stabilization_check", None, {})
+
+    assert result["overall_pass"] is True
+    assert result["skipped"] is False
+    assert result["checks"]["totals"]["pass"] is True