fix(runtime): fail closed on offline artifact misses

src/k1link/web/app.py

@@ -63,6 +63,10 @@ from k1link.web.plugin_runtime import (
 )
 from k1link.web.polygon_api import build_polygon_router, configured_polygon_runs_root
 from k1link.web.runtime_diagnostics import configure_scanner_diagnostics
+from k1link.web.runtime_readiness import (
+    BackgroundReconcilerReadiness,
+    build_runtime_readiness,
+)
 from k1link.web.session_api import build_session_router
 from k1link.web.system_telemetry_api import build_system_telemetry_router
 from k1link.web.viewer_diagnostics_api import build_viewer_diagnostics_router
@@ -167,6 +171,7 @@ session_perception_epoch_store = (
     else None
 )
 map_gateway_proxy = MapGatewayProxy(MapGatewayConfiguration.from_environment())
+recording_reconciler_readiness = BackgroundReconcilerReadiness()
 
 
 def _prepare_recorded_media_for_launch(
@@ -281,10 +286,11 @@ async def _recording_preparation_reconciler() -> None:
                     newly_finalized,
                 )
             known_finalized = finalized
-        except Exception:
+            recording_reconciler_readiness.record_success()
+        except Exception as exc:
             # A transient filesystem/catalog failure must not permanently
             # disable preparation of sessions completed later in the run.
-            pass
+            recording_reconciler_readiness.record_failure(exc)
         await asyncio.sleep(2.0)
 
 
@@ -339,18 +345,16 @@ async def request_validation_error_handler(
 
 @app.get("/api/health")
 def health() -> dict[str, Any]:
-    runtime_health = plugin_environment.runtime_health
-    runtimes_ready = all(item["status"] == "ready" for item in runtime_health)
-    return {
-        "ok": runtimes_ready,
-        "status": "ok" if runtimes_ready else "degraded",
-        "service": "mission-core-control-plane",
-        "version": __version__,
-        "plugin_runtimes": {
-            "ready": sum(item["status"] == "ready" for item in runtime_health),
-            "total": len(runtime_health),
-        },
-    }
+    return build_runtime_readiness(
+        version=__version__,
+        plugin_runtime_health=plugin_environment.runtime_health,
+        recording_materializer=session_recording_materializer,
+        artifact_gateway=session_artifact_gateway,
+        map_gateway_configured=map_gateway_proxy.configured,
+        ffmpeg_available=_ffmpeg is not None,
+        ffprobe_available=_ffprobe is not None,
+        reconciler=recording_reconciler_readiness,
+    )
 
 
 @app.get("/api/v1/device-plugins")