feat(canvas): 云端 Agent - 完成策略分层、节点能力注册与可解释审批改造

backend/internal/app/cloud_agent_mutation.go

@@ -19,6 +19,7 @@ type cloudAgentMutationInput struct {
 	AfterSnapshotHash  string
 	BeforeJSON         string
 	HasSubmittedTask   bool
+	Preview            *cloudAgentApprovalPreview
 }
 
 func cloudAgentMutationRecorderForRun(runID string) cloudAgentMutationRecorder {