feat(annotation): 实现标注结果同步到知识管理功能

- 在知识条目实体中新增来源数据集ID和文件ID字段
- 实现标注编辑器中同步标注结果到知识管理的服务逻辑
- 添加知识同步服务类处理标注到知识条目的转换和同步
- 实现通过下载接口获取文本内容的独立服务模块
- 更新知识条目查询接口支持按来源数据集和文件ID过滤
- 自动创建和关联标注项目对应的知识集
- 支持文本和Markdown文件的内容合并标注结果
- 添加同步过程中的错误处理和日志记录机制

runtime/datamate-python/app/module/annotation/service/text_fetcher.py

@@ -0,0 +1,56 @@
+from __future__ import annotations
+
+import httpx
+from fastapi import HTTPException
+
+from app.core.config import settings
+from app.core.logging import get_logger
+
+logger = get_logger(__name__)
+
+
+async def fetch_text_content_via_download_api(dataset_id: str, file_id: str) -> str:
+    """通过下载接口读取文本内容"""
+    base = settings.datamate_backend_base_url.rstrip("/")
+    url = f"{base}/data-management/datasets/{dataset_id}/files/{file_id}/download"
+
+    try:
+        async with httpx.AsyncClient(timeout=30.0, follow_redirects=True) as client:
+            resp = await client.get(url)
+            resp.raise_for_status()
+
+            content_length = resp.headers.get("content-length")
+            if content_length:
+                try:
+                    if int(content_length) > settings.editor_max_text_bytes:
+                        raise HTTPException(
+                            status_code=413,
+                            detail=f"文本文件过大，限制 {settings.editor_max_text_bytes} 字节",
+                        )
+                except ValueError:
+                    # content-length 非法则忽略，走实际长度判断
+                    pass
+
+            data = resp.content
+            if len(data) > settings.editor_max_text_bytes:
+                raise HTTPException(
+                    status_code=413,
+                    detail=f"文本文件过大，限制 {settings.editor_max_text_bytes} 字节",
+                )
+
+            # TEXT POC：默认按 UTF-8 解码，不可解码字符用替换符处理
+            return data.decode("utf-8", errors="replace")
+
+    except HTTPException:
+        raise
+    except httpx.HTTPStatusError as exc:
+        logger.error(
+            "读取文本失败: dataset=%s, file=%s, http=%s",
+            dataset_id,
+            file_id,
+            exc.response.status_code,
+        )
+        raise HTTPException(status_code=502, detail="读取文本失败（下载接口返回错误）")
+    except Exception as exc:
+        logger.error("读取文本失败: dataset=%s, file=%s, err=%s", dataset_id, file_id, exc)
+        raise HTTPException(status_code=502, detail="读取文本失败（下载接口调用异常）")