fix(settings): normalize empty validation policy lists

.gitignore

@@ -157,3 +157,4 @@ backend/coverage_unit.json
 backend/coverage_integration.json
 backend/unit_run.log
 backend/integration_run.log
+ss-tools-0.7.0.bundle

backend/src/schemas/settings.py

@@ -6,7 +6,7 @@
 
 from datetime import datetime, time
 
-from pydantic import BaseModel, ConfigDict, Field
+from pydantic import BaseModel, ConfigDict, Field, field_validator
 
 
 # #region Schemas.Settings.NotificationChannel [TYPE Class]
@@ -94,6 +94,11 @@ class ValidationPolicyResponse(ValidationPolicyBase):
 
     model_config = ConfigDict(from_attributes=True)
 
+    @field_validator('dashboard_ids', 'schedule_days', mode='before')
+    @classmethod
+    def empty_list_if_none(cls, v):
+        return v or []
+
 
 # #endregion Schemas.Settings.ValidationPolicyResponse