chore(client): AppConfig 默认连生产 jiu.51yanmei.com

BASE_URL/PUBLIC_URL/ABOUT_URL 默认值改为线上，flutter run 不带
--dart-define 即连生产；需本地后端时显式 --dart-define 覆盖。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bupi8Kdqkfx2N5acFsHTx5

client/lib/core/config/app_config.dart

@@ -1,22 +1,20 @@
 /// 集中管理应用配置，通过 --dart-define=KEY=value 注入环境变量
 ///
-/// 开发默认值：http://localhost:8080
-/// 生产部署示例：flutter run \
-///   --dart-define=BASE_URL=http://192.168.1.100:8080 \
-///   --dart-define=SHOP_NAME=强朋友名酒行 \
-///   --dart-define=SHOP_ADDRESS=贵州省贵阳市云岩区中华北路88号 \
-///   --dart-define=SHOP_PHONE=0851-12345678
+/// 默认值 = 线上服务（jiu.51yanmei.com）：本地 flutter run 不带 define 也连生产。
+/// 需连本地后端时显式覆盖：flutter run \
+///   --dart-define=BASE_URL=http://localhost:8080 \
+///   --dart-define=PUBLIC_URL=http://localhost:8081
 class AppConfig {
   const AppConfig._();
 
   static const _baseUrl = String.fromEnvironment(
     'BASE_URL',
-    defaultValue: 'http://localhost:8080',
+    defaultValue: 'https://jiu.51yanmei.com',
   );
 
   static const _publicUrl = String.fromEnvironment(
     'PUBLIC_URL',
-    defaultValue: 'http://localhost:8081',
+    defaultValue: 'https://jiu.51yanmei.com',
   );
 
   static const shopName = String.fromEnvironment(