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/member_favorite/view.dart

@@ -172,8 +172,8 @@ class _MemberFavoriteState extends State<MemberFavorite>
                   height: 98,
                   child: MemberFavItem(
                     item: item,
-                    callback: (res) {
-                      if (res == true) {
+                    onDelete: (isDeleted) {
+                      if (isDeleted ?? false) {
                         _controller.favState
                           ..value.mediaListResponse?.list?.remove(item)
                           ..refresh();