address review: nil-guard reloaded tasks and SyncTask to ActiveTopology

- skip nil entries from LoadAllTaskStates (corrupted state)
- re-sync restored tasks with MaintenanceIntegration so ActiveTopology
  (in-memory, empty on startup) knows about them; otherwise GetNextTask's
  AssignTask rejects them as unknown and they never get assigned

weed/admin/maintenance/maintenance_queue.go

@@ -52,9 +52,13 @@ func (mq *MaintenanceQueue) LoadTasksFromPersistence() error {
 	}
 
 	var terminal []string
+	var restored []*MaintenanceTask
 	mq.mutex.Lock()
 	requeued := 0
 	for _, task := range tasks {
+		if task == nil {
+			continue
+		}
 		switch task.Status {
 		case TaskStatusPending, TaskStatusAssigned, TaskStatusInProgress:
 			task.Status = TaskStatusPending
@@ -62,6 +66,7 @@ func (mq *MaintenanceQueue) LoadTasksFromPersistence() error {
 			task.Progress = 0
 			mq.tasks[task.ID] = task
 			mq.pendingTasks = append(mq.pendingTasks, task)
+			restored = append(restored, snapshotTask(task))
 			requeued++
 		default:
 			terminal = append(terminal, task.ID)
@@ -75,6 +80,15 @@ func (mq *MaintenanceQueue) LoadTasksFromPersistence() error {
 	})
 	mq.mutex.Unlock()
 
+	// ActiveTopology is in-memory and starts empty, so restored tasks must be
+	// re-synced or GetNextTask's AssignTask would reject them as unknown and
+	// they'd sit pending forever. Done outside the lock, like the retry path.
+	if mq.integration != nil {
+		for _, task := range restored {
+			mq.integration.SyncTask(task)
+		}
+	}
+
 	// Delete stale terminal files outside the lock to avoid blocking on disk I/O.
 	for _, id := range terminal {
 		mq.deleteTaskState(id)