fix(health): suppress 404 when health monitor disabled + fix audit test assertion

- Sidebar.svelte: defer healthStore.refresh() until feature flags confirm
  health_monitor is enabled; skip entirely when disabled
- health.js: remove throw error from catch block — log and return null
  instead, preventing 'Uncaught (in promise)' on expected 404
- test_report_audit_immutability.py: fix mock assertions —
  audit_service uses logger.reason/reflect/explore, not logger.info
- HealthStore and Sidebar now produce zero network noise when
  FEATURES__HEALTH_MONITOR=false

backend/src/plugins/translate/orchestrator.py

@@ -238,6 +238,15 @@ class TranslationOrchestrator:
                     "run_id": run.id,
                     "error": str(e),
                 })
+                # Rollback the session if it's in a broken state (e.g. after a
+                # failed flush from a previous exception in executor.execute_run).
+                # Without this, subsequent flush()/commit() calls raise
+                # "This Session's transaction has been rolled back".
+                try:
+                    self.db.rollback()
+                except Exception:
+                    pass
+                run = self.db.merge(run)
                 run.status = "FAILED"
                 run.error_message = f"Translation execution failed: {e}"
                 run.completed_at = datetime.now(UTC)
@@ -887,6 +896,7 @@ class TranslationOrchestrator:
                 "id": run.id,
                 "job_id": run.job_id,
                 "status": run.status,
+                "trigger_type": run.trigger_type,
                 "started_at": run.started_at.isoformat() if run.started_at else None,
                 "completed_at": run.completed_at.isoformat() if run.completed_at else None,
                 "error_message": run.error_message,