feat: 前端页面优化与入库任务重试/删除

- 概览与检索合并为单一概览页
- 类目/文档管理/入库整合为树形目录知识库页（Library），支持文档搜索
- 入库进度改为右侧 Drawer，支持任务详情、重试、删除
- 后端新增任务重试与删除接口

tests/test_ingest_task_api.py

@@ -19,6 +19,8 @@ class FakeManager:
         self.tasks = tasks or {}
         self.task_id = task_id
         self.submitted: list[DocumentInput] = []
+        self.retry_result: str | None = None
+        self.delete_result: bool = False
 
     async def submit(self, doc: DocumentInput) -> str:
         self.submitted.append(doc)
@@ -27,6 +29,12 @@ class FakeManager:
     async def get(self, task_id: str) -> dict[str, Any] | None:
         return self.tasks.get(task_id)
 
+    async def retry(self, task_id: str) -> str | None:
+        return self.retry_result
+
+    async def delete(self, task_id: str) -> bool:
+        return self.delete_result
+
 
 def _task(task_id: str, status: str, **extra: Any) -> dict[str, Any]:
     """构造一条任务记录（时间字段为固定 ISO8601 字符串）"""
@@ -159,3 +167,44 @@ def test_post_empty_text_creates_no_task(client: TestClient, monkeypatch: pytest
     body = resp.json()
     assert body["code"] == 1001
     assert manager.submitted == []
+
+
+def test_retry_task_returns_202(client: TestClient, monkeypatch: pytest.MonkeyPatch) -> None:
+    """POST tasks/{id}/retry：HTTP 202，返回新 task_id 与 pending 状态"""
+    manager = FakeManager()
+    manager.retry_result = "new-task-7"
+    _inject_manager(monkeypatch, manager)
+
+    resp = client.post("/api/v1/documents/tasks/t-failed/retry")
+
+    assert resp.status_code == 202
+    body = resp.json()
+    assert body["code"] == 0
+    assert body["data"]["task_id"] == "new-task-7"
+    assert body["data"]["status"] == "pending"
+
+
+def test_retry_task_not_found(client: TestClient, monkeypatch: pytest.MonkeyPatch) -> None:
+    """POST tasks/{id}/retry：manager 返回 None → code=1004"""
+    manager = FakeManager()
+    manager.retry_result = None
+    _inject_manager(monkeypatch, manager)
+
+    resp = client.post("/api/v1/documents/tasks/nope/retry")
+
+    body = resp.json()
+    assert body["code"] == 1004
+
+
+def test_delete_task(client: TestClient, monkeypatch: pytest.MonkeyPatch) -> None:
+    """DELETE tasks/{id}：删除成功 → deleted=true"""
+    manager = FakeManager()
+    manager.delete_result = True
+    _inject_manager(monkeypatch, manager)
+
+    resp = client.delete("/api/v1/documents/tasks/t-x")
+
+    body = resp.json()
+    assert body["code"] == 0
+    assert body["data"]["task_id"] == "t-x"
+    assert body["data"]["deleted"] is True