fix(tasks): 任务队列 - 限制缓存回源并修复并发租约与过期写入

backend/internal/service/task_terminal.go

@@ -27,7 +27,7 @@ type taskTerminalCoordinator struct {
 
 type taskTerminalRepository interface {
 	Task(id string) (*model.Task, error)
-	UpdateTaskTerminalState(id string, expected model.TaskStatus, status model.TaskStatus, stage string, errorText string, completedAt time.Time) (bool, error)
+	UpdateTaskTerminalState(id string, owner string, expected model.TaskStatus, status model.TaskStatus, stage string, errorText string, completedAt time.Time) (bool, error)
 }
 
 type taskBillingLifecycle interface {
@@ -248,9 +248,13 @@ func (c *taskTerminalCoordinator) handleSuccess(task *model.Task) error {
 func (c *taskTerminalCoordinator) markTerminalState(task *model.Task) error {
 	completedAt := time.Now()
 	task.CompletedAt = &completedAt
-	if _, err := c.repo.UpdateTaskTerminalState(task.ID, model.TaskStatusRunning, task.Status, task.Stage, task.Error, completedAt); err != nil {
+	updated, err := c.repo.UpdateTaskTerminalState(task.ID, task.LeaseOwner, model.TaskStatusRunning, task.Status, task.Stage, task.Error, completedAt)
+	if err != nil {
 		return fmt.Errorf("写入任务终态失败：%w", err)
 	}
+	if !updated {
+		return repository.ErrTaskStateConflict
+	}
 	return nil
 }