新增: 工作流审批取消端到端（StateMachine Arc 共享 + 取消 IPC 注册表）

- StateMachine 内部 HashMap→Arc<Mutex<HashMap>>，clone 共享底层
- DagExecutor 加 state_machine() 访问器
- AppState 加 workflow_state_registry（execution_id→StateMachine）
- run_workflow 注册执行器状态机 + 完成清理
- cancel_workflow_node IPC 经 execution_id 取共享引用 set_cancelled，直达 HumanNode 轮询
- 前端取消按钮 + cancelHumanApproval store 方法
- 加 clone_shares 单测验证共享语义

src/stores/project.ts

@@ -244,6 +244,22 @@ function createStore() {
     }
   }
 
+  /** 取消当前待审批节点（调 cancel_workflow_node IPC 置节点 Cancelled） */
+  async function cancelHumanApproval() {
+    if (!state.pendingApproval) return
+
+    try {
+      await invoke('cancel_workflow_node', {
+        execution_id: state.pendingApproval.execution_id,
+        node_id: state.pendingApproval.node_id,
+      })
+      // 清除待审批状态
+      state.pendingApproval = null
+    } catch (error) {
+      console.error('取消审批失败:', error)
+    }
+  }
+
   function stopEventListener() {
     if (_eventUnlisten) {
       try {
@@ -284,7 +300,7 @@ function createStore() {
     loadIdeas, createIdea, updateIdea, deleteIdea, evaluateIdea, promoteIdea,
     // workflow actions
     runWorkflow, loadWorkflowExecutions, startEventListener, stopEventListener, clearLiveEvents,
-    approveHumanApproval, pendingApproval: computed(() => state.pendingApproval),
+    approveHumanApproval, cancelHumanApproval, pendingApproval: computed(() => state.pendingApproval),
     // computed
     stats,
   })

src/views/ProjectDetail.vue

@@ -189,6 +189,7 @@
           </div>
         </div>
         <div class="modal-actions">
+          <button class="btn btn-ghost" @click="handleCancelApproval">取消</button>
           <button class="btn btn-ghost" @click="showApprovalDialog = false">{{ $t('projectDetail.approvalLater') }}</button>
         </div>
       </div>
@@ -383,6 +384,12 @@ async function handleApproval(decision: string) {
   showApprovalDialog.value = false
 }
 
+// ── 取消审批（调 cancel_workflow_node IPC 置节点 Cancelled）──
+async function handleCancelApproval() {
+  await store.cancelHumanApproval()
+  showApprovalDialog.value = false
+}
+
 // ── 删除项目(软删 → 回收站,可恢复)──
 async function handleDelete() {
   const p = currentProject.value