fix: Update type hints to use newer Python syntax

- Replace Dict, List, Optional with dict, list,  < /dev/null |  None syntax
- Fix abstract method implementation in message.py
- Improve type annotations and function return types
- Remove unreachable code in get_current_task_tool.py
- Refactor HTML elements to use style attributes

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/plugins/PFC/pfc_utils.py

@@ -18,6 +18,7 @@ def get_items_from_json(
 
     Args:
         content: 包含JSON的文本
+        private_name: 私聊名称
         *items: 要提取的字段名
         default_values: 字段的默认值，格式为 {字段名: 默认值}
         required_types: 字段的必需类型，格式为 {字段名: 类型}