识图与文件上传/预览:可配置视觉模型 + 修复上传与回显

后端:
- 新增可配置识图模型(config: vision.model_name/prompt/max_tokens)。配置后 view_image 委托该模型识别并返回文字结果,文本主模型也能“看图”;未配置时回退到主模型自带视觉能力。新增 deerflow/models/vision.py 与 VisionConfig。
- 修复 Windows 上传全部报 unsafe:open_upload_file_no_symlink 不再强制要求 POSIX 专有的 O_NOFOLLOW,缺失时降级(仍用 lstat/fstat 防符号链接),Windows 追加 O_BINARY。
- 修复 normalize_input 丢弃 human 消息 additional_kwargs:保留 files/client_ts 等,使上传文件能回传到 UI 并被 UploadsMiddleware 识别。
- 约束 agent 行为:上传图片时引导只用 view_image,禁止用 read_file/grep/bash/python 解析图片字节;view_image 工具说明同步加固。
- 启用文档转换(uploads.auto_convert_documents),PDF/Word/Excel/PPT 自动转 Markdown 供 read_file/grep 读取。
- 订正若干模型错误的 supports_vision 标记。

前端:
- 修复上传文件不回显:parseUploadedFiles 不再因 "(empty)" 提前返回。
- 修复 artifact 401 破图:改用带 Authorization 头的 apiFetch 取 blob 显示(新增 useAuthedObjectUrl)。
- 新增上传文件预览弹窗:点击卡片可查看图片/文本/Markdown、Office(读转换后的 .md)、PDF;文件卡片改为可点击。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

offline-backend-20260512/backend/app/gateway/services.py

@@ -84,13 +84,23 @@ def normalize_input(raw_input: dict[str, Any] | None) -> dict[str, Any]:
         converted = []
         for msg in messages:
             if isinstance(msg, dict):
-                role = msg.get("role", msg.get("type", "user"))
                 content = msg.get("content", "")
-                if role in ("user", "human"):
-                    converted.append(HumanMessage(content=content))
-                else:
-                    # TODO: handle other message types (system, ai, tool)
-                    converted.append(HumanMessage(content=content))
+                # Preserve additional_kwargs (e.g. uploaded `files`, `client_ts`,
+                # `prompt_prefix`) and optional id/name so they round-trip through
+                # the checkpoint to the UI and to UploadsMiddleware. Dropping them
+                # here previously made uploaded files invisible in the chat and
+                # broke the per-message ask-time timestamp.
+                msg_kwargs: dict[str, Any] = {"content": content}
+                extra = msg.get("additional_kwargs")
+                if isinstance(extra, dict) and extra:
+                    msg_kwargs["additional_kwargs"] = extra
+                if msg.get("id"):
+                    msg_kwargs["id"] = msg["id"]
+                if msg.get("name"):
+                    msg_kwargs["name"] = msg["name"]
+                # TODO: handle other message types (system, ai, tool); for now all
+                # inbound dict messages are treated as human turns.
+                converted.append(HumanMessage(**msg_kwargs))
             else:
                 converted.append(msg)
         return {**raw_input, "messages": converted}