feat(mobile): UI-03 photos and share pages (17-20)

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

apps/mobile/lib/pages/album_detail_page.dart

@@ -219,12 +219,9 @@ class _AlbumDetailPageState extends ConsumerState<AlbumDetailPage> {
   void _shareQr() {
     final album = _album;
     if (album == null) return;
-    showDialog<void>(
-      context: context,
-      builder: (_) => ShareQrDialog(
-        publicToken: album.publicToken,
-        albumTitle: albumDisplayTitle(album, AppLocalizations.of(context).localeName),
-      ),
+    // UI-03 页面 19：分享从对话框升级为全屏分享页（真实封面 + 二维码）。
+    Navigator.of(context).push(
+      MaterialPageRoute<void>(builder: (_) => ShareQrPage(album: album)),
     );
   }