Add back button on ticket and task detail screens

lib/screens/tasks/task_detail_screen.dart

@@ -2400,7 +2400,21 @@ class _TaskDetailScreenState extends ConsumerState<TaskDetailScreen>
             final detailsCard = Card(
               child: Padding(
                 padding: const EdgeInsets.all(20),
-                child: SingleChildScrollView(child: detailsContent),
+                child: SingleChildScrollView(
+                  child: Column(
+                    crossAxisAlignment: CrossAxisAlignment.start,
+                    children: [
+                      Align(
+                        alignment: Alignment.topLeft,
+                        child: IconButton(
+                          icon: const Icon(Icons.arrow_back),
+                          onPressed: () => Navigator.of(context).pop(),
+                        ),
+                      ),
+                      detailsContent,
+                    ],
+                  ),
+                ),
               ),
             );
 
@@ -2605,27 +2619,24 @@ class _TaskDetailScreenState extends ConsumerState<TaskDetailScreen>
               ),
             );
 
-            if (isWide) {
+            final mainContent = isWide
-              return Row(
+                ? Row(
                     children: [
                       Expanded(flex: 2, child: detailsCard),
                       const SizedBox(width: 16),
                       Expanded(flex: 3, child: tabbedCard),
                     ],
-              );
+                  )
-            }
+                : Stack(
-
-            // Mobile/tablet: allow vertical scrolling of detail card while
-            // keeping the chat/activity panel filling the remaining viewport
-            // (and scrolling internally). Use a CustomScrollView to provide a
-            // bounded height for the tabbed card via SliverFillRemaining.
-            return Stack(
                     children: [
                       CustomScrollView(
                         slivers: [
                           SliverToBoxAdapter(child: detailsCard),
                           const SliverToBoxAdapter(child: SizedBox(height: 12)),
-                    SliverFillRemaining(hasScrollBody: true, child: tabbedCard),
+                          SliverFillRemaining(
+                            hasScrollBody: true,
+                            child: tabbedCard,
+                          ),
                         ],
                       ),
                       if (isRetrieving)
@@ -2633,9 +2644,8 @@ class _TaskDetailScreenState extends ConsumerState<TaskDetailScreen>
                           child: AbsorbPointer(
                             absorbing: true,
                             child: Container(
-                        color: Theme.of(
+                              color: Theme.of(context).colorScheme.surface
-                          context,
+                                  .withAlpha((0.35 * 255).round()),
-                        ).colorScheme.surface.withAlpha((0.35 * 255).round()),
                               alignment: Alignment.topCenter,
                               padding: const EdgeInsets.only(top: 36),
                               child: SizedBox(
@@ -2655,7 +2665,9 @@ class _TaskDetailScreenState extends ConsumerState<TaskDetailScreen>
                                           ),
                                         ),
                                         SizedBox(width: 12),
-                                  Expanded(child: Text('Retrieving updates…')),
+                                        Expanded(
+                                          child: Text('Retrieving updates…'),
+                                        ),
                                       ],
                                     ),
                                   ),
@@ -2666,6 +2678,8 @@ class _TaskDetailScreenState extends ConsumerState<TaskDetailScreen>
                         ),
                     ],
                   );
+
+            return mainContent;
           },
         ),
       ),

lib/screens/tickets/ticket_detail_screen.dart

@@ -199,7 +199,21 @@ class _TicketDetailScreenState extends ConsumerState<TicketDetailScreen> {
           final detailsCard = Card(
             child: Padding(
               padding: const EdgeInsets.all(20),
-              child: SingleChildScrollView(child: detailsContent),
+              child: SingleChildScrollView(
+                child: Column(
+                  crossAxisAlignment: CrossAxisAlignment.start,
+                  children: [
+                    Align(
+                      alignment: Alignment.topLeft,
+                      child: IconButton(
+                        icon: const Icon(Icons.arrow_back),
+                        onPressed: () => Navigator.of(context).pop(),
+                      ),
+                    ),
+                    detailsContent,
+                  ],
+                ),
+              ),
             ),
           );
 
@@ -437,27 +451,23 @@ class _TicketDetailScreenState extends ConsumerState<TicketDetailScreen> {
             ),
           );
 
-          if (isWide) {
+          final mainContent = isWide
-            return Row(
+              ? Row(
                   children: [
                     Expanded(flex: 2, child: detailsCard),
                     const SizedBox(width: 16),
                     Expanded(flex: 3, child: messagesCard),
                   ],
-            );
+                )
-          }
+              : Column(
-
-          // Mobile: avoid nesting scrollables. detailsCard itself is
-          // scrollable if it grows tall, and the messages area takes the
-          // remaining space so the chat list can always receive touch
-          // gestures and never end up offscreen.
-          return Column(
                   children: [
                     detailsCard,
                     const SizedBox(height: 12),
                     Expanded(child: messagesCard),
                   ],
                 );
+
+          return mainContent;
         },
       ),
     );