feat: app 端 ui 设计完成

wei_ai_app/lib/models/scenario.dart

@@ -0,0 +1,21 @@
+class Scenario {
+  final String id;
+  final String title;
+  final String category;
+  final String cover;
+  final String duration;
+  final String intensity; // 'Low' | 'Medium' | 'High' | 'Extreme'
+  final bool isLocked;
+  final List<String> tags;
+
+  const Scenario({
+    required this.id,
+    required this.title,
+    required this.category,
+    required this.cover,
+    required this.duration,
+    required this.intensity,
+    required this.isLocked,
+    required this.tags,
+  });
+}