Add multi-select support to pmshare panel (#1779)

* Add multi-select support to share panel

- Replace single selection index with per-user selected flag
- Allow sending to multiple selected users
- Add sending state to prevent multiple clicks
- Update default selection logic to mark first user as selected

* 简化代码逻辑

* update

Signed-off-by: bggRGjQaUbCoE <githubaccount56556@proton.me>

---------

Signed-off-by: lesetong <oscarlbw@qq.com>
Co-authored-by: bggRGjQaUbCoE <githubaccount56556@proton.me>

lib/pages/fav/video/view.dart

@@ -63,7 +63,7 @@ class _FavVideoPageState extends State<FavVideoPage>
                     heroTag: heroTag,
                     item: item,
                     onTap: () async {
-                      var res = await Get.toNamed(
+                      final res = await Get.toNamed(
                         '/favDetail',
                         arguments: item,
                         parameters: {