fix(app): 全链路验证修复 — 编译错误/CORS/迁移/启动脚本

前端修复:
- calendar_page: 移除不存在的 JournalEntry.content getter
- responsive_scaffold: 移除不存在的 notchThickness 参数
- splash_page: SingleTickerProvider → TickerProvider (多 AnimationController)
- profile_page: UserRoleType.name → .code (修复运行时崩溃)
- 导入缺失的 user.dart

后端修复:
- class_service: generate_class_code 取 UUID 后6位(随机部分)避免碰撞
- diary_role_seed: 移除不存在的 id 列,使用复合主键 ON CONFLICT

基础设施:
- config/default.toml: CORS 改为通配符(开发模式)
- scripts/dev.sh: 统一启动脚本(自动清理端口)
- docs/opendesign/: Open Design 设计规格 HTML 原型稿

验证结果: flutter analyze 0 error, cargo test 77/77 通过, 17个页面全部渲染正常

app/lib/features/stickers/views/sticker_library_page.dart

@@ -3,6 +3,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:nuanji_app/core/theme/app_colors.dart';
+import 'package:nuanji_app/core/theme/app_radius.dart';
 import 'package:nuanji_app/data/remote/api_client.dart';
 import '../bloc/sticker_bloc.dart';
 
@@ -135,7 +136,7 @@ class _StickerPackCard extends StatelessWidget {
     return Card(
       elevation: 0,
       shape: RoundedRectangleBorder(
-        borderRadius: BorderRadius.circular(16),
+        borderRadius: AppRadius.mdBorder,
         side: BorderSide(color: colorScheme.outlineVariant),
       ),
       child: InkWell(
@@ -144,7 +145,7 @@ class _StickerPackCard extends StatelessWidget {
             SnackBar(content: Text('打开贴纸包: ${pack.name}')),
           );
         },
-        borderRadius: BorderRadius.circular(16),
+        borderRadius: AppRadius.mdBorder,
         child: Padding(
           padding: const EdgeInsets.all(16),
           child: Column(
@@ -156,7 +157,7 @@ class _StickerPackCard extends StatelessWidget {
                 height: 64,
                 decoration: BoxDecoration(
                   color: colorScheme.primaryContainer.withValues(alpha: 0.3),
-                  borderRadius: BorderRadius.circular(16),
+                  borderRadius: AppRadius.mdBorder,
                 ),
                 alignment: Alignment.center,
                 child: Text(