接单平台等级 CRUD 完善，修复默认分类停用被重置

- 等级面板支持编辑、启用/停用切换、删除（默认等级与使用中等级受保护）
- 新增等级删除接口及使用量校验
- 修复默认分类停用后被 ensureWorkerPlatformDefaults 重置为启用的问题，默认分类仅不存在时创建
- 分类操作后改为显式刷新列表

apps/frontend/src/pages/admin/AdminWorkerPlatformPage.tsx

@@ -40,6 +40,7 @@ import {
   createAdminMockWorkOrder,
   creditAdminWorkerWallet,
   deleteAdminWorkCategory,
+  deleteAdminWorkerLevel,
   fetchAdminWorkerFinanceConfig,
   fetchAdminWorkerFinanceRequests,
   fetchAdminWorkCategories,
@@ -1043,9 +1044,7 @@ function CategoriesPanel() {
   })
 
   async function refreshCategories() {
-    await queryClient.invalidateQueries({
-      queryKey: ['admin-worker-platform-categories'],
-    })
+    await categoriesQuery.refetch()
   }
 
   function startEdit(category: WorkCategory) {
@@ -1880,6 +1879,28 @@ function LevelsPanel() {
     queryFn: () => fetchAdminWorkerLevels(),
   })
   const [form] = Form.useForm()
+  const [editingLevel, setEditingLevel] = useState<WorkerLevel | null>(null)
+  const [deletingLevel, setDeletingLevel] = useState<WorkerLevel | null>(null)
+
+  async function refreshLevels() {
+    await levelsQuery.refetch()
+  }
+
+  function startEdit(level: WorkerLevel) {
+    setEditingLevel(level)
+    form.setFieldsValue({
+      levelKey: level.levelKey,
+      name: level.name,
+      depositFreeAmount: level.depositFreeAmount,
+      maxActiveOrders: level.maxActiveOrders,
+      upgradeThreshold: level.upgradeThreshold,
+    })
+  }
+
+  function cancelEdit() {
+    setEditingLevel(null)
+    form.resetFields()
+  }
 
   async function saveLevel(values: {
     levelKey: string
@@ -1890,15 +1911,47 @@ function LevelsPanel() {
   }) {
     try {
       await saveAdminWorkerLevel(values)
-      message.success('等级已保存')
-      await queryClient.invalidateQueries({
-        queryKey: ['admin-worker-platform-levels'],
-      })
+      message.success(editingLevel ? '等级已更新' : '等级已保存')
+      cancelEdit()
+      await refreshLevels()
     } catch (error) {
       message.error(error instanceof Error ? error.message : '保存失败')
     }
   }
 
+  async function toggleLevel(level: WorkerLevel) {
+    try {
+      await saveAdminWorkerLevel({
+        levelKey: level.levelKey,
+        name: level.name,
+        depositFreeAmount: level.depositFreeAmount,
+        maxActiveOrders: level.maxActiveOrders,
+        upgradeThreshold: level.upgradeThreshold,
+        status: level.status === 'active' ? 'disabled' : 'active',
+      })
+      message.success(level.status === 'active' ? '等级已停用' : '等级已启用')
+      await refreshLevels()
+    } catch (error) {
+      message.error(error instanceof Error ? error.message : '操作失败')
+    }
+  }
+
+  async function submitDelete() {
+    if (!deletingLevel) return
+    try {
+      await deleteAdminWorkerLevel(deletingLevel.levelId)
+      message.success('等级已删除')
+      setDeletingLevel(null)
+      await refreshLevels()
+      await queryClient.invalidateQueries({
+        queryKey: ['admin-worker-platform-workers'],
+      })
+    } catch (error) {
+      message.error(error instanceof Error ? error.message : '删除失败')
+      setDeletingLevel(null)
+    }
+  }
+
   const columns: TableColumnsType<WorkerLevel> = [
     { title: '等级', dataIndex: 'name' },
     { title: '标识', dataIndex: 'levelKey' },
@@ -1908,12 +1961,40 @@ function LevelsPanel() {
     },
     { title: '最大同时接单', dataIndex: 'maxActiveOrders' },
     { title: '升级所需累计完成', dataIndex: 'upgradeThreshold' },
-    { title: '状态', dataIndex: 'status' },
+    {
+      title: '状态',
+      width: 110,
+      render: (_, row) => (
+        <Tag color={row.status === 'active' ? 'green' : 'default'}>
+          {row.status === 'active' ? '启用' : '停用'}
+        </Tag>
+      ),
+    },
+    {
+      title: '操作',
+      width: 240,
+      render: (_, row) => (
+        <Space wrap>
+          <Button size="small" onClick={() => startEdit(row)}>
+            编辑
+          </Button>
+          <Button size="small" onClick={() => toggleLevel(row)}>
+            {row.status === 'active' ? '停用' : '启用'}
+          </Button>
+          <Button size="small" danger onClick={() => setDeletingLevel(row)}>
+            删除
+          </Button>
+        </Space>
+      ),
+    },
   ]
 
   return (
     <section className="platform-panel-stack">
-      <Card title="保存等级" bordered={false}>
+      <Card
+        title={editingLevel ? `编辑等级：${editingLevel.name}` : '保存等级'}
+        bordered={false}
+      >
         <Form
           form={form}
           layout="inline"
@@ -1954,9 +2035,12 @@ function LevelsPanel() {
             <InputNumber min={0} max={100000} />
           </Form.Item>
           <Form.Item>
-            <Button type="primary" htmlType="submit">
-              保存
-            </Button>
+            <Space>
+              <Button type="primary" htmlType="submit">
+                保存
+              </Button>
+              {editingLevel ? <Button onClick={cancelEdit}>取消</Button> : null}
+            </Space>
           </Form.Item>
         </Form>
       </Card>
@@ -1969,6 +2053,19 @@ function LevelsPanel() {
           pagination={false}
         />
       </Card>
+      <Modal
+        title="删除等级"
+        open={Boolean(deletingLevel)}
+        onOk={submitDelete}
+        onCancel={() => setDeletingLevel(null)}
+        okButtonProps={{ danger: true }}
+        okText="删除"
+        cancelText="取消"
+      >
+        <Typography.Text>
+          确定删除等级「{deletingLevel?.name}」？正在使用该等级的打手将无法删除，需先调整。
+        </Typography.Text>
+      </Modal>
     </section>
   )
 }

apps/frontend/src/services/admin/worker-platform.ts

@@ -49,12 +49,19 @@ export function deleteAdminWorkCategory(categoryId: number) {
   )
 }
 
+export function deleteAdminWorkerLevel(levelId: number) {
+  return apiDelete<{ deleted: boolean }>(
+    `/api/v1/admin/worker-platform/levels/${levelId}`,
+  )
+}
+
 export function saveAdminWorkerLevel(payload: {
   levelKey: string
   name: string
   depositFreeAmount?: number
   maxActiveOrders?: number
   upgradeThreshold?: number
+  status?: string
 }) {
   return apiPost<{ level: WorkerLevel }>(
     '/api/v1/admin/worker-platform/levels',