test(admin-v2): Phase 2 frontend tests — 61 tests for 5 pages

- Billing (13 tests): plan cards, prices, limits, usage bars, payment flow
- ScheduledTasks (16 tests): CRUD table, schedule/target types, color tags
- Knowledge (12 tests): 4 tabs, items/categories/search/analytics panels
- Roles (12 tests): roles + permission templates tabs
- ConfigSync (8 tests): sync log viewer with action labels

Fix: Knowledge.tsx missing </Select> and </Modal> closing tags (JSX parse error)
Fix: tests/setup.ts added ResizeObserver mock for ProTable compatibility

admin-v2/src/pages/Knowledge.tsx

@@ -183,6 +183,7 @@ function CategoriesPanel() {
                 .map((c) => (
                   <Select.Option key={c.id} value={c.id}>{c.name}</Select.Option>
                 ))}
+            </Select>
           </Form.Item>
           <Form.Item name="icon" label="图标">
             <Input placeholder="如 📚" />
@@ -454,6 +455,7 @@ function ItemsPanel() {
           },
         ]}
       />
+      </Modal>
     </div>
   )
 }