admin: fix capacity leak in maintenance system by preserving Task IDs (#8214)

* admin: fix capacity leak in maintenance system by preserving Task IDs

Preserve the original TaskID generated during detection and sync task
states (Assign/Complete/Retry) with ActiveTopology. This ensures that
capacity reserved during task assignment is properly released when a
task completes or fails, preventing 'need 9, have 0' capacity exhaustion.

Fixes https://github.com/seaweedfs/seaweedfs/issues/8202

* Update weed/admin/maintenance/maintenance_queue.go

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

* Update weed/admin/maintenance/maintenance_queue.go

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

* test: rename ActiveTopologySync to TaskIDPreservation

Rename the test case to more accurately reflect its scope, as suggested
by the code review bot.

* Add TestMaintenanceQueue_ActiveTopologySync to verify task state synchronization and capacity management

* Implement task assignment rollback and add verification test

* Enhance ActiveTopology.CompleteTask to support pending tasks

* Populate storage impact in MaintenanceIntegration.SyncTask

* Release capacity in RemoveStaleWorkers when worker becomes unavailable

* Release capacity in MaintenanceManager.CancelTask when pending task is cancelled

* Sync reloaded tasks with ActiveTopology in LoadTasksFromPersistence

* Add verification tests for consistent capacity management lifecycle

* Add TestMaintenanceQueue_RetryCapacitySync to verify capacity tracking during retries

---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

weed/admin/maintenance/maintenance_manager.go

@@ -603,6 +603,13 @@ func (mm *MaintenanceManager) CancelTask(taskID string) error {
 			}
 		}
 
+		// Notify ActiveTopology to release capacity
+		if mm.scanner != nil && mm.scanner.integration != nil {
+			if at := mm.scanner.integration.GetActiveTopology(); at != nil {
+				_ = at.CompleteTask(taskID)
+			}
+		}
+
 		glog.V(2).Infof("Cancelled task %s", taskID)
 		return nil
 	}