refactor: chats drawer ui/ux tweaks

lib/features/navigation/widgets/chats_drawer.dart

@@ -79,6 +79,7 @@ class _ChatsDrawerState extends ConsumerState<ChatsDrawer> {
     if (Platform.isIOS) {
       // Use Cupertino-style pull-to-refresh on iOS
       final scroll = CustomScrollView(
+        key: const PageStorageKey<String>('chats_drawer_scroll'),
         controller: _listController,
         physics: const AlwaysScrollableScrollPhysics(),
         slivers: [
@@ -100,6 +101,7 @@ class _ChatsDrawerState extends ConsumerState<ChatsDrawer> {
       child: Scrollbar(
         controller: _listController,
         child: ListView(
+          key: const PageStorageKey<String>('chats_drawer_scroll'),
           controller: _listController,
           physics: const AlwaysScrollableScrollPhysics(),
           padding: padding,
@@ -1604,14 +1606,19 @@ class _ConversationTile extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final theme = context.conduitTheme;
-    return Material(
+    final Color selectedBackground =
-      color: Colors.transparent,
+        theme.buttonPrimary.withValues(alpha: 0.10); // subtle highlight
+    final Color selectedBorder = theme.buttonPrimary.withValues(alpha: 0.60);
+
+    return Semantics(
+      selected: selected,
+      button: true,
+      child: Material(
+        color: selected ? selectedBackground : Colors.transparent,
         shape: RoundedRectangleBorder(
           borderRadius: BorderRadius.circular(AppBorderRadius.md),
           side: BorderSide(
-          color: selected
+            color: selected ? selectedBorder : theme.dividerColor,
-              ? theme.buttonPrimary.withValues(alpha: 0.5)
-              : theme.dividerColor,
             width: BorderWidth.regular,
           ),
         ),
@@ -1619,7 +1626,28 @@ class _ConversationTile extends StatelessWidget {
           borderRadius: BorderRadius.circular(AppBorderRadius.md),
           onTap: isLoading ? null : onTap,
           onLongPress: onLongPress,
-        child: Padding(
+          child: Stack(
+            children: [
+              // Left accent bar for active conversation
+              AnimatedPositioned(
+                duration: const Duration(milliseconds: 160),
+                curve: Curves.easeOut,
+                left: 0,
+                top: 0,
+                bottom: 0,
+                child: AnimatedContainer(
+                  duration: const Duration(milliseconds: 160),
+                  width: selected ? 3.0 : 0.0,
+                  decoration: BoxDecoration(
+                    color: theme.buttonPrimary,
+                    borderRadius: const BorderRadius.only(
+                      topLeft: Radius.circular(AppBorderRadius.md),
+                      bottomLeft: Radius.circular(AppBorderRadius.md),
+                    ),
+                  ),
+                ),
+              ),
+              Padding(
                 padding: const EdgeInsets.symmetric(
                   horizontal: Spacing.md,
                   vertical: Spacing.sm,
@@ -1633,7 +1661,8 @@ class _ConversationTile extends StatelessWidget {
                         overflow: TextOverflow.ellipsis,
                         style: AppTypography.standard.copyWith(
                           color: theme.textPrimary,
-                    fontWeight: selected ? FontWeight.w600 : FontWeight.w500,
+                          fontWeight:
+                              selected ? FontWeight.w700 : FontWeight.w500,
                         ),
                       ),
                     ),
@@ -1670,6 +1699,9 @@ class _ConversationTile extends StatelessWidget {
                   ],
                 ),
               ),
+            ],
+          ),
+        ),
       ),
     );
   }