feat(fusion_accounting_assets): asset anomaly persisted model

- 3 anomaly types: behind_schedule, ahead_of_schedule, low_utilization
- 3 severity levels: low, medium, high
- expected / actual / variance_pct (mirrors anomaly_detection service output)
- 4-state lifecycle: new -> acknowledged -> resolved (or dismissed)
- action_acknowledge / action_dismiss / action_resolve transitions
- ondelete='cascade' on asset_id (anomalies follow the asset)
- 4 new tests (63 total)

Made-with: Cursor

fusion_accounting_assets/tests/__init__.py

@@ -7,3 +7,4 @@ from . import test_fusion_asset
 from . import test_fusion_asset_depreciation_line
 from . import test_fusion_asset_category
 from . import test_fusion_asset_disposal
+from . import test_fusion_asset_anomaly