feat: expanded sliver app bar (#19827)

* use mutex

* feat: cool app bar

* animation

* adapt to more pages

* animation

* better animation

* fix: asset count

* Revert "fix: asset count"

This reverts commit 673a5b264b.

* fix: asset count

* fix: shaky animation on Android

* tunning

* offset SizedBox to fix scroll jump on multiselect

---------

Co-authored-by: shenlong-tanwen <139912620+shalong-tanwen@users.noreply.github.com>

mobile/lib/domain/models/album/album.model.dart

@@ -11,7 +11,7 @@ enum AlbumUserRole {
 }
 
 // Model for an album stored in the server
-class Album {
+class RemoteAlbum {
   final String id;
   final String name;
   final String ownerId;
@@ -24,7 +24,7 @@ class Album {
   final int assetCount;
   final String ownerName;
 
-  const Album({
+  const RemoteAlbum({
     required this.id,
     required this.name,
     required this.ownerId,
@@ -57,7 +57,7 @@ class Album {
 
   @override
   bool operator ==(Object other) {
-    if (other is! Album) return false;
+    if (other is! RemoteAlbum) return false;
     if (identical(this, other)) return true;
     return id == other.id &&
         name == other.name &&

mobile/lib/domain/services/remote_album.service.dart

@@ -8,26 +8,26 @@ class RemoteAlbumService {
 
   const RemoteAlbumService(this._repository);
 
-  Future<List<Album>> getAll() {
+  Future<List<RemoteAlbum>> getAll() {
     return _repository.getAll();
   }
 
-  List<Album> sortAlbums(
-    List<Album> albums,
+  List<RemoteAlbum> sortAlbums(
+    List<RemoteAlbum> albums,
     RemoteAlbumSortMode sortMode, {
     bool isReverse = false,
   }) {
     return sortMode.sortFn(albums, isReverse);
   }
 
-  List<Album> searchAlbums(
-    List<Album> albums,
+  List<RemoteAlbum> searchAlbums(
+    List<RemoteAlbum> albums,
     String query,
     String? userId, [
     QuickFilterMode filterMode = QuickFilterMode.all,
   ]) {
     final lowerQuery = query.toLowerCase();
-    List<Album> filtered = albums;
+    List<RemoteAlbum> filtered = albums;
 
     // Apply text search filter
     if (query.isNotEmpty) {

mobile/lib/domain/services/timeline.service.dart

@@ -210,6 +210,9 @@ class TimelineService {
   Future<void> preCacheAssets(int index) =>
       _mutex.run(() => _loadAssets(index, math.min(5, _totalAssets - index)));
 
+  BaseAsset getRandomAsset() =>
+      _buffer.elementAt(math.Random().nextInt(_buffer.length));
+
   BaseAsset getAsset(int index) {
     if (!hasRange(index, 1)) {
       throw RangeError(