Refine datasource trigger flow and CLI output

backend/app/services/collectors/base.py

@@ -282,6 +282,7 @@ class BaseCollector(ABC):
                 "execution_time_seconds": (datetime.now(UTC) - start_time).total_seconds(),
             }
         except asyncio.CancelledError:
+            await db.rollback()
             task.status = "cancelled"
             task.phase = "cancelled"
             task.error_message = "Collection cancelled by operator and rolled back"
@@ -297,6 +298,7 @@ class BaseCollector(ABC):
             await self._publish_task_update(force=True)
             raise
         except Exception as e:
+            await db.rollback()
             task.status = "failed"
             task.phase = "failed"
             task.error_message = str(e)