refactor: 优化日志输出，仅在调试模式下启用

- 为所有 print 语句添加 kDebugMode 检查
- 更新 KRLogUtil 工具类，Release 模式下禁用日志输出
- 优化 18 个文件中的 335+ 条日志语句
- 提升 Release 版本性能并增强安全性

(cherry picked from commit 301f1510ba81fe94fb08e013ca80b3ca708a2e15)

lib/app/services/api_service/kr_auth_api.dart

@@ -1,4 +1,4 @@
-import 'dart:io';
+import 'dart:io' as io;
 import 'dart:math';
 import 'dart:convert';
 
@@ -21,6 +21,8 @@ import '../kr_device_info_service.dart';
 import '../kr_site_config_service.dart';
 import '../../common/app_config.dart';
 import 'package:dio/dio.dart' as dio;
+import 'package:kaer_with_panels/app/services/singbox_imp/kr_sing_box_imp.dart';
+import 'package:flutter/foundation.dart';
 
 class KRAuthApi {
   /// 检查账号是否已注册（仅支持邮箱）
@@ -465,17 +467,17 @@ class KRAuthApi {
   }
 
    String _kr_getUserAgent() {
-    if (Platform.isAndroid) {
+    if (io.Platform.isAndroid) {
       return 'android';
-    } else if (Platform.isIOS) {
+    } else if (io.Platform.isIOS) {
       return 'ios';
-    } else if (Platform.isMacOS) {
+    } else if (io.Platform.isMacOS) {
       return 'mac';
-    } else if (Platform.isWindows) {
+    } else if (io.Platform.isWindows) {
       return 'windows';
-    } else if (Platform.isLinux) {
+    } else if (io.Platform.isLinux) {
       return 'linux';
-    } else if (Platform.isFuchsia) {
+    } else if (io.Platform.isFuchsia) {
       return 'harmony';
     } else {
       return 'unknown';