feat(chat): refactor chat message handling and introduce private messaging support

- Updated `uni_message_sender.py` to allow for private messaging by removing the mandatory group ID and adding user ID handling.
- Enhanced chat history retrieval and clearing functions in `routes.py` and `service.py` to support both group and private chat scenarios.
- Introduced a new `ChatScrollContext` for managing message scrolling and highlighting in the chat UI.
- Created a `ListItemEditorHookFactory` for rendering a rich UI editor for list items in configuration settings, replacing the previous JSON text display.
- Improved message serialization for consistent display in chat history.
- Added detailed logging for chat history operations and error handling.

Co-authored-by: Copilot <copilot@github.com>

src/webui/config_schema.py

@@ -70,11 +70,15 @@ class ConfigSchemaGenerator:
     ) -> Dict[str, Any]:
         field_docs = config_class.get_class_field_docs()
         field_type = cls._map_field_type(annotation)
+        raw_description = field_docs.get(field_name, field_info.description or "")
+        # `_wrap_` 标记在配置类 docstring 中表示该说明应作为块级注释（独立成行）
+        # 在前端展示时把它转为换行符，使描述以新行起始或在中间换行
+        description = raw_description.replace("_wrap_", "\n").strip("\n")
         schema: Dict[str, Any] = {
             "name": field_name,
             "type": field_type,
             "label": field_name,
-            "description": field_docs.get(field_name, field_info.description or ""),
+            "description": description,
             "required": field_info.is_required(),
         }