feat: SAC 0.7.0 display_name columns and event severity overrides

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/schemas/list_models.py

@@ -32,6 +32,7 @@ class EventSummary(BaseModel):
     event_id: str
     host_id: int
     hostname: str
+    display_name: str | None = None
     occurred_at: datetime
     received_at: datetime
     category: str