feat(background): 添加录制状态持久化和Tab切换处理

- 实现录制状态存储到本地storage，包括isRecording、recordingTabId、events和startTime
- 添加loadRecorderState和saveRecorderState函数用于状态管理
- 监听Tab切换事件，当切换离开录制Tab时发出警告并通知popup
- 监听Tab关闭事件，自动停止录制并清理状态
- 添加录制状态同步检查，确保content script状态一致
- 在开始录制前检查是否已在录制状态，避免重复录制
- 添加错误处理返回详细错误信息
- 优化回放HTML样式和脚本加载方式
- 添加Tab切换消息通信协议支持

utils/messages.tsx

@@ -9,6 +9,7 @@ export const messages = {
     to: {
       stopped: 'popup:stopped',
       started: 'popup:started',
+      tabChanged: 'popup:tab-changed',
     },
     checkStatus: 'popup:check-status',
     ready: 'popup:ready',
@@ -33,10 +34,11 @@ export const messages = {
 
 interface ProtocolMap {
   // --- Popup 相关 ---
-  'popup:start': () => { ok: boolean };
-  'popup:stop': () => { ok: boolean };
+  'popup:start': () => { ok: boolean; error?: string };
+  'popup:stop': () => { ok: boolean; error?: string };
   'popup:started': () => void;
   'popup:stopped': () => void;
+  'popup:tab-changed': (data: { currentTabId: number; recordingTabId: number | undefined }) => void;
   'popup:check-status': () => { active: boolean; startTime?: number };
   'popup:ready': () => void;