perf(extensions): load store summaries and check updates asynchronously (#1583)

ui/flutter/lib/shared/widgets/app_empty_state.dart

@@ -0,0 +1,108 @@
+import 'package:flutter/widgets.dart';
+import 'package:shadcn_flutter/shadcn_flutter.dart' as shad;
+
+import '../theme/app_design_tokens.dart';
+import '../theme/app_palette.dart';
+import 'app_tooltip.dart';
+import 'app_empty_illustration.dart';
+
+export 'app_empty_illustration.dart' show AppEmptyIllustrationType;
+
+/// Shared empty/error surface used by task and extension views.
+class AppEmptyState extends StatelessWidget {
+  const AppEmptyState({
+    super.key,
+    required this.message,
+    required this.illustration,
+    this.action,
+    this.illustrationKey,
+  });
+
+  final String message;
+  final AppEmptyIllustrationType illustration;
+  final Widget? action;
+  final Key? illustrationKey;
+
+  @override
+  Widget build(BuildContext context) {
+    final palette = AppPalette.of(context);
+    return Center(
+      child: SingleChildScrollView(
+        child: ConstrainedBox(
+          constraints: const BoxConstraints(maxWidth: 360),
+          child: Padding(
+            padding: const EdgeInsets.all(24),
+            child: Column(
+              mainAxisSize: MainAxisSize.min,
+              children: [
+                AppEmptyIllustration(key: illustrationKey, type: illustration),
+                const SizedBox(height: 18),
+                Text(
+                  message,
+                  textAlign: TextAlign.center,
+                  style: TextStyle(color: palette.textPrimary, fontSize: 17, fontWeight: FontWeight.w700),
+                ),
+                if (action != null) ...[const SizedBox(height: AppDesignTokens.space24), action!],
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}
+
+/// Places the action inside localized guidance, matching every empty state.
+class AppEmptyStateAction extends StatelessWidget {
+  const AppEmptyStateAction({
+    super.key,
+    required this.icon,
+    required this.label,
+    required this.hint,
+    required this.onPressed,
+    this.buttonKey,
+  });
+
+  final IconData icon;
+  final String label;
+  final String Function(String action) hint;
+  final VoidCallback onPressed;
+  final Key? buttonKey;
+
+  @override
+  Widget build(BuildContext context) {
+    const actionMarker = '\uFFFC';
+    final parts = hint(actionMarker).split(actionMarker);
+    return Text.rich(
+      TextSpan(
+        children: [
+          TextSpan(text: parts.first.trimRight()),
+          WidgetSpan(
+            alignment: PlaceholderAlignment.middle,
+            child: Padding(
+              padding: const EdgeInsets.symmetric(horizontal: 8),
+              child: AppTooltip(
+                message: label,
+                child: Semantics(
+                  label: label,
+                  child: SizedBox.square(
+                    dimension: 30,
+                    child: shad.IconButton.outline(
+                      key: buttonKey,
+                      density: shad.ButtonDensity.compact,
+                      onPressed: onPressed,
+                      icon: Icon(icon, size: 16),
+                    ),
+                  ),
+                ),
+              ),
+            ),
+          ),
+          TextSpan(text: parts.last.trimLeft()),
+        ],
+      ),
+      textAlign: TextAlign.center,
+      style: TextStyle(color: AppPalette.of(context).textMuted, fontSize: 13),
+    );
+  }
+}