refactor: optimize ChatsDrawer for performance and smooth scrolling

- Added cacheExtent to the ListView in ChatsDrawer for improved scrolling smoothness.
- Updated activeConversationProvider selection to only rebuild tiles when their selected state changes, enhancing performance.
- Replaced Padding with RepaintBoundary to optimize rendering during drag operations.
- Changed clipBehavior to Clip.hardEdge for better performance in avatar rendering.

lib/features/navigation/widgets/chats_drawer.dart

@@ -108,6 +108,8 @@ class _ChatsDrawerState extends ConsumerState<ChatsDrawer> {
           key: const PageStorageKey<String>('chats_drawer_scroll'),
           controller: _listController,
           physics: const AlwaysScrollableScrollPhysics(),
+          // Precache a bit ahead for perceived smoothness when scrolling.
+          cacheExtent: 800,
           padding: padding,
           children: children,
         ),
@@ -1068,7 +1070,10 @@ class _ChatsDrawerState extends ConsumerState<ChatsDrawer> {
   }
 
   Widget _buildTileFor(dynamic conv, {bool inFolder = false}) {
-    final isActive = ref.watch(activeConversationProvider)?.id == conv.id;
+    // Only rebuild this tile when its own selected state changes.
+    final isActive = ref.watch(
+      activeConversationProvider.select((c) => c?.id == conv.id),
+    );
     final title = conv.title?.isEmpty == true ? 'Chat' : (conv.title ?? 'Chat');
     final theme = context.conduitTheme;
     final bool isLoadingSelected =
@@ -1124,7 +1129,8 @@ class _ChatsDrawerState extends ConsumerState<ChatsDrawer> {
       },
     );
 
-    return Padding(
+    return RepaintBoundary(
+      child: Padding(
         padding: EdgeInsets.only(
           bottom: Spacing.xs,
           left: inFolder ? Spacing.md : 0,
@@ -1157,6 +1163,7 @@ class _ChatsDrawerState extends ConsumerState<ChatsDrawer> {
           }),
           child: tile,
         ),
+      ),
     );
   }
 
@@ -1375,7 +1382,9 @@ class _ChatsDrawerState extends ConsumerState<ChatsDrawer> {
                         width: BorderWidth.thin,
                       ),
                     ),
-                    clipBehavior: Clip.antiAlias,
+                    // Hard-edge clipping is cheaper than anti-aliased clipping
+                    // and sufficient for avatar squares with rounded corners.
+                    clipBehavior: Clip.hardEdge,
                     child: UserAvatar(
                       size: 36,
                       imageUrl: avatarUrl,