api: POST /apply converge endpoint; enabled in summaries

- Replace POST /deploy with POST /apply (name + plan), returning the
  enacted diff (activated/restarted/deactivated/unchanged). /config/apply
  now delegates to core apply() too, so there's one convergence path.
- Retire /services/{name}/start and /stop (keep /restart as the
  imperative bounce). Drop install/uninstall from program actions — tool/
  static activation is convergence now.
- Surface `enabled` on ServiceSummary/JobSummary/DeploymentSummary so the
  UI can show and toggle desired state.
- conftest: drop the obsolete config_editor.get_registry patch (apply_config
  no longer reads the registry directly).

59 API tests pass; route table shows /apply (no /deploy), /restart only.

castle-api/tests/test_health.py

@@ -99,6 +99,13 @@ class TestServicesList:
         svc = next(s for s in data if s["id"] == "test-svc")
         assert "schedule" not in svc
 
+    def test_enabled_flows_through(self, client: TestClient) -> None:
+        """ServiceSummary surfaces the declared `enabled` state (default True)."""
+        response = client.get("/services")
+        data = response.json()
+        svc = next(s for s in data if s["id"] == "test-svc")
+        assert svc["enabled"] is True
+
     def test_no_installed_field(self, client: TestClient) -> None:
         """ServiceSummary does not have installed field."""
         response = client.get("/services")