修正切换和国旗问题

(cherry picked from commit bec2464da85e981636077276de36b2ea5f6c40f4)

lib/app/widgets/kr_country_flag.dart

@@ -37,12 +37,38 @@ class KRCountryFlag extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    // 🔍 调试日志
+    print('🏳️ KRCountryFlag.build 被调用');
+    print('  - 原始 countryCode: "$countryCode"');
+    print('  - countryCode.isEmpty: ${countryCode.isEmpty}');
+    print('  - countryCode.length: ${countryCode.length}');
+
+    final processedCode = _getCountryCode(countryCode);
+    print('  - 处理后 code: "$processedCode"');
+
+    // 如果国家代码为空，显示占位符
+    if (countryCode.isEmpty) {
+      print('  ❌ 国家代码为空，显示占位符');
+      return Container(
+        width: width ?? 50.w,
+        height: height ?? 50.w,
+        decoration: BoxDecoration(
+          color: Colors.grey[300],
+          shape: isCircle ? BoxShape.circle : BoxShape.rectangle,
+          borderRadius: !isCircle ? BorderRadius.circular(8.w) : null,
+        ),
+        child: Icon(Icons.flag, color: Colors.grey[600], size: 24.w),
+      );
+    }
+
     // 计算实际尺寸
     final double actualWidth = width ?? 50.w;
     final double actualHeight = maintainSize ? actualWidth : (height ?? 50.w);
-    
+
+    print('  ✅ 尝试加载国旗: $processedCode');
+
     Widget flagWidget = CountryFlag.fromCountryCode(
-      _getCountryCode(countryCode),
+      processedCode,
       width: actualWidth,
       height: actualHeight,
     );