feat(ui): unify child surfaces and show web task creation in a modal (#1633)

ui/flutter/lib/features/home/presentation/pages/home_page.dart

@@ -11,7 +11,7 @@ import '../../../../app/application/app_runtime_controller.dart';
 import '../../../../core/capabilities/app_capabilities.dart';
 import '../../../../core/utils/breakpoints.dart';
 import '../../../../core/utils/file_explorer.dart';
-import '../../../../core/window/app_window_launcher.dart';
+import '../../../../app/router/app_router.dart';
 import '../../../../core/window/app_window_chrome.dart';
 import '../../../../shared/theme/app_design_tokens.dart';
 import '../../../../shared/theme/app_palette.dart';
@@ -580,19 +580,7 @@ class _HomePageState extends ConsumerState<HomePage> {
     }
   }
 
-  void _handleAddTask() {
-    if (!Util.isDesktop()) {
-      context.go('/create');
-      return;
-    }
-    unawaited(
-      AppWindowLauncher.openCreateTaskWindow().then((opened) {
-        if (!opened && mounted) {
-          context.go('/create');
-        }
-      }),
-    );
-  }
+  void _handleAddTask() => unawaited(AppRouter.openCreateTask());
 
   Future<void> _runTaskAction(Future<void> Function() action) async {
     try {

ui/flutter/lib/features/home/presentation/widgets/primary_rail.dart

@@ -1,5 +1,4 @@
-import 'package:flutter/material.dart' show Icons;
-import 'package:flutter/widgets.dart';
+import 'package:shadcn_flutter/shadcn_flutter.dart';
 import 'package:go_router/go_router.dart';
 
 import '../../../../core/window/app_window_chrome.dart';
@@ -28,7 +27,21 @@ class PrimaryRail extends StatelessWidget {
         children: [
           SizedBox(
             height: AppDesignTokens.contentHeaderHeight,
-            child: const Center(child: GopeedAppMark(key: ValueKey('primary-rail-app-mark'))),
+            child: Center(
+              child: AppTooltip(
+                message: context.l10n.task,
+                child: Semantics(
+                  label: context.l10n.task,
+                  button: true,
+                  child: GhostButton(
+                    key: const ValueKey('primary-rail-home-button'),
+                    density: ButtonDensity.icon,
+                    onPressed: () => context.go('/'),
+                    child: const ExcludeSemantics(child: GopeedAppMark(key: ValueKey('primary-rail-app-mark'))),
+                  ),
+                ),
+              ),
+            ),
           ),
           const SizedBox(height: AppDesignTokens.space8),
           _RailItem(