fix(lyric): 修复桌面歌词窗口首次打开无歌词问题

歌词窗口 Vue 加载完成后发送 lyric-ready 信号，主窗口收到后
发送完整歌词数据，替代不可靠的延迟猜测方案

src/preload/index.d.ts

@@ -19,6 +19,7 @@ interface API {
   sendSong: (data: any) => void;
   unblockMusic: (id: number, data: any, enabledSources?: string[]) => Promise<any>;
   onLyricWindowClosed: (callback: () => void) => void;
+  onLyricWindowReady: (callback: () => void) => void;
   getAppUpdateState: () => Promise<AppUpdateState>;
   checkAppUpdate: (manual?: boolean) => Promise<AppUpdateState>;
   downloadAppUpdate: () => Promise<AppUpdateState>;

src/preload/index.ts

@@ -28,6 +28,10 @@ const api = {
   onLyricWindowClosed: (callback: () => void) => {
     ipcRenderer.on('lyric-window-closed', () => callback());
   },
+  // 歌词窗口就绪事件（Vue 加载完成，可以接收数据）
+  onLyricWindowReady: (callback: () => void) => {
+    ipcRenderer.on('lyric-window-ready', () => callback());
+  },
   getAppUpdateState: () => ipcRenderer.invoke('app-update:get-state') as Promise<AppUpdateState>,
   checkAppUpdate: (manual = false) =>
     ipcRenderer.invoke('app-update:check', { manual }) as Promise<AppUpdateState>,