TF-4141 Fix separator still not reactive to selection mode changes.

lib/features/base/mixin/ai_scribe_mixin.dart

@@ -15,6 +15,10 @@ mixin AiScribeMixin {
     return session.getAICapability(accountId);
   }
 
+  /// Returns whether the AI Scribe endpoint is available for the given session and account.
+  ///
+  /// Returns `true` if the account has AI capability with an available Scribe endpoint,
+  /// `false` otherwise (including when session or accountId are null).
   bool isAIScribeEndpointAvailable({Session? session, AccountId? accountId}) {
     final aiCapability = getAICapability(
       session: session,

lib/features/mailbox/presentation/extensions/list_mailbox_node_extension.dart

@@ -26,7 +26,7 @@ extension ListMailboxNodeExtension on List<MailboxNode> {
   }
 
   /// Insert [newNode] after the first mailbox matching [priorities].
-  /// If none match, inserts at the beginning.
+  /// If no priorities match (or [priorities] is empty), inserts at the beginning.
   void insertAfterByPriority(
     MailboxNode newNode,
     List<bool Function(MailboxNode)> priorities,

lib/features/mailbox/presentation/widgets/mailbox_item_widget.dart

@@ -330,6 +330,7 @@ class _MailboxItemWidgetState extends State<MailboxItemWidget> {
     }
 
     // Dragging action-required mailboxes must not show highlight
+    // because they're virtual folders that don't accept email drops
     if (widget.isDraggingMailbox && widget.mailboxNode.item.isActionRequired) {
       return AppColor.colorBgDesktop;
     }

lib/features/search/email/presentation/search_email_view.dart

@@ -676,13 +676,13 @@ class SearchEmailView extends GetWidget<SearchEmailController>
             listPresentationEmail[index],
           ),
           separatorBuilder: (context, index) {
+            return Obx(() {
               final isMobile = PlatformInfo.isMobile;
               final isInactive =
                   controller.selectionMode.value == SelectMode.INACTIVE;
 
-            final dividerColor = isMobile
+              final dividerColor =
-                ? null
+                  isMobile ? null : (isInactive ? null : Colors.white);
-                : (isInactive ? null : Colors.white);
 
               final padding = isMobile
                   ? SearchEmailUtils.getPaddingItemListMobile(
@@ -698,6 +698,7 @@ class SearchEmailView extends GetWidget<SearchEmailController>
                 padding: padding,
                 child: Divider(color: dividerColor),
               );
+            });
           },
         )
     );