Add generation harness runtime

backend/app/services/provider_router.py

@@ -10,7 +10,7 @@ from app.core.logging import get_logger
 from app.services.adapters import AdapterConfig, AdapterRegistry
 from app.services.adapters.text.models import StoryOutput
 from app.services.cost_tracker import cost_tracker
-from app.services.generation_jobs import record_generation_event
+from app.services.harness.trace import TraceRecorder
 from app.services.provider_cache import get_providers
 from app.services.provider_metrics import health_checker, metrics_collector
 from app.services.provider_policy import (
@@ -67,8 +67,7 @@ async def _record_provider_event_if_present(
     if db is None or job is None:
         return
 
-    await record_generation_event(
-        db,
+    await TraceRecorder(db).record_step(
         job=job,
         story_id=story_id,
         event_type=event_type,