refactor: 统一代码格式，调整多行代码换行风格

对多个文件进行代码格式化调整，将长行参数拆分为多行书写，提升代码可读性，包括：
- 调整函数定义、调用的多行换行格式
- 优化列表、元组、字典的多行排版
- 新增README.md项目说明文档

app/api/v1/document.py

@@ -57,30 +57,44 @@ def _get_task_manager() -> IngestTaskManager:
         except Exception:
             logger.warning("Redis 缓存不可用，入库任务状态仅保留在内存", exc_info=True)
             redis = None
-        _task_manager = IngestTaskManager(ingester=_get_ingester(), redis=redis, settings=Settings())
+        _task_manager = IngestTaskManager(
+            ingester=_get_ingester(), redis=redis, settings=Settings()
+        )
     return _task_manager
 
 
 def _allowed_extensions() -> set[str]:
     """解析 settings.upload_allowed_extensions 逗号分隔字符串为扩展名集合（全小写、含点号）"""
-    return {ext.strip().lower() for ext in settings.upload_allowed_extensions.split(",") if ext.strip()}
+    return {
+        ext.strip().lower()
+        for ext in settings.upload_allowed_extensions.split(",")
+        if ext.strip()
+    }
 
 
 @router.post("/documents")
-async def ingest_document(doc: DocumentInput, user: AuthUser = Depends(get_current_user)) -> JSONResponse:
+async def ingest_document(
+    doc: DocumentInput, user: AuthUser = Depends(get_current_user)
+) -> JSONResponse:
     """文档入库入口：登记异步任务并返回 202 + task_id，入库结果经任务查询端点获取"""
     if not doc.text.strip():
         raise ApiError(1001, "文档内容不能为空")
     task_id = await _get_task_manager().submit(doc)
-    return JSONResponse(status_code=202, content=ok({"task_id": task_id, "status": "pending"}))
+    return JSONResponse(
+        status_code=202, content=ok({"task_id": task_id, "status": "pending"})
+    )
 
 
 @router.post("/documents/upload")
 async def upload_document(
-    file: UploadFile = File(..., description="上传的文件（.txt/.md/.html/.htm/.pdf/.docx）"),
+    file: UploadFile = File(
+        ..., description="上传的文件（.txt/.md/.html/.htm/.pdf/.docx）"
+    ),
     title: str = Form(default="", description="可选标题，默认取原文件名去扩展"),
     source: str = Form(default="", description="可选来源标识，默认 file:{原文件名}"),
-    metadata: str = Form(default="", description='可选元数据 JSON 字符串，如 \'{"author":"x"}\''),
+    metadata: str = Form(
+        default="", description='可选元数据 JSON 字符串，如 \'{"author":"x"}\''
+    ),
     user: AuthUser = Depends(get_current_user),
 ) -> JSONResponse:
     """文件上传入库入口：校验 → 提取文本 → 落盘 → 提交异步入库流水线
@@ -129,9 +143,16 @@ async def upload_document(
                 "original_size_bytes": str(len(content)),
             }
         )
-        logger.info("上传文件已落盘", doc_id=doc_id, saved_path=saved_path, size=len(content))
+        logger.info(
+            "上传文件已落盘", doc_id=doc_id, saved_path=saved_path, size=len(content)
+        )
     except Exception:
-        logger.warning("上传文件落盘失败，仅做文本入库", doc_id=doc_id, filename=original_filename, exc_info=True)
+        logger.warning(
+            "上传文件落盘失败，仅做文本入库",
+            doc_id=doc_id,
+            filename=original_filename,
+            exc_info=True,
+        )
 
     # 5. 合并用户传入的 metadata（落盘元数据优先级更高，不与用户键冲突）
     if metadata.strip():
@@ -150,7 +171,9 @@ async def upload_document(
         source = f"file:{original_filename}"
 
     # 7. 提交入库流水线
-    doc_input = DocumentInput(text=text, title=title, source=source, metadata=metadata_dict)
+    doc_input = DocumentInput(
+        text=text, title=title, source=source, metadata=metadata_dict
+    )
     task_id = await _get_task_manager().submit(doc_input)
 
     return JSONResponse(
@@ -160,7 +183,9 @@ async def upload_document(
 
 
 @router.get("/documents/tasks/{task_id}")
-async def get_ingest_task(task_id: str, user: AuthUser = Depends(get_current_user)) -> dict[str, Any]:
+async def get_ingest_task(
+    task_id: str, user: AuthUser = Depends(get_current_user)
+) -> dict[str, Any]:
     """查询入库任务状态：含 task_id/status/created_at/updated_at，done 附 result，failed 附 error"""
     task = await _get_task_manager().get(task_id)
     if task is None:
@@ -184,7 +209,9 @@ async def list_documents(
 
 
 @router.get("/documents/{doc_id}")
-async def get_document(doc_id: str, user: AuthUser = Depends(get_current_user)) -> dict[str, Any]:
+async def get_document(
+    doc_id: str, user: AuthUser = Depends(get_current_user)
+) -> dict[str, Any]:
     """获取文档详情：L1 记录 + L2/L3 节点 + chunks 数量"""
     try:
         detail = await _get_qdrant().get_doc_detail(doc_id)
@@ -197,11 +224,15 @@ async def get_document(doc_id: str, user: AuthUser = Depends(get_current_user))
 
 
 @router.delete("/documents/{doc_id}")
-async def delete_document(doc_id: str, user: AuthUser = Depends(require_admin)) -> dict[str, Any]:
+async def delete_document(
+    doc_id: str, user: AuthUser = Depends(require_admin)
+) -> dict[str, Any]:
     """删除文档：四层集合中该 doc_id 的所有点；幂等，不存在也返回成功（删除数全 0）"""
     try:
         deleted = await _get_qdrant().delete_by_doc_id(doc_id)
     except Exception as exc:
         logger.error("文档删除失败", doc_id=doc_id, error=str(exc))
         raise ApiError(2000, f"文档删除失败: {exc}") from exc
-    return ok({"doc_id": doc_id, "deleted": deleted, "deleted_total": sum(deleted.values())})
+    return ok(
+        {"doc_id": doc_id, "deleted": deleted, "deleted_total": sum(deleted.values())}
+    )