feat(utils): 添加文档URL助手以支持多语言文档链接

新增 doc_url_helper.dart 工具文件，提供 docLangPath、privacyPolicyUrl 和 userAgreementUrl 函数
根据当前语言环境动态生成对应的文档链接，支持多种语言版本
替换登录页、个人资料页和隐私政策弹窗中的硬编码URL，提高代码复用性和可维护性

lib/core/utils/doc_url_helper.dart

@@ -0,0 +1,27 @@
+import 'package:get/get.dart';
+
+/// 根据当前语言返回 doc 目录名，如 "zh_cn"、"en"、"fr"
+String docLangPath() {
+  final lang = Get.locale?.languageCode ?? 'en';
+  final country = Get.locale?.countryCode?.toUpperCase() ?? '';
+  if (lang == 'zh') {
+    if (country == 'CN') return 'zh_cn';
+    if (country == 'HK') return 'zh_hk';
+    return 'zh_tw';
+  }
+  const supported = [
+    'ar', 'bg', 'cs', 'da', 'de', 'el', 'es', 'et', 'fa', 'fi', 'fr',
+    'hi', 'hr', 'hu', 'id', 'is', 'it', 'ja', 'ko', 'lt', 'lv', 'ms',
+    'nb', 'nl', 'pl', 'pt', 'ro', 'ru', 'sk', 'sl', 'sr', 'sv', 'th',
+    'tl', 'tr', 'uk', 'vi',
+  ];
+  return supported.contains(lang) ? lang : 'en';
+}
+
+/// 构建隐私政策 URL
+String privacyPolicyUrl() =>
+    'https://www.voitrans.net/doc/${docLangPath()}/privacy_policy.html';
+
+/// 构建用户协议 URL
+String userAgreementUrl() =>
+    'https://www.voitrans.net/doc/${docLangPath()}/user_agreement.html';

lib/modules/common/widgets/privacy_policy_dialog.dart

@@ -3,6 +3,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter_screenutil/flutter_screenutil.dart';
 import 'package:get/get.dart';
 import '../webview_page.dart';
+import '../../../core/utils/doc_url_helper.dart';
 
 /// 隐私政策弹窗组件
 class PrivacyPolicyDialog extends StatelessWidget {
@@ -77,15 +78,8 @@ class PrivacyPolicyDialog extends StatelessWidget {
                         alignment: PlaceholderAlignment.middle,
                         child: GestureDetector(
                           onTap: () {
-                            String url =
-                                'https://www.voitrans.net/doc/privacy_policy.html';
-                            if (Get.locale?.languageCode != 'zh' ||
-                                Get.locale?.countryCode != 'CN') {
-                              url =
-                                  'https://www.voitrans.net/doc/privacy_policy_en.html';
-                            }
                             Get.to(() => WebViewPage(
-                                  url: url,
+                                  url: privacyPolicyUrl(),
                                   title: 'privacyPolicy'.tr,
                                 ));
                           },
@@ -109,15 +103,8 @@ class PrivacyPolicyDialog extends StatelessWidget {
                         alignment: PlaceholderAlignment.middle,
                         child: GestureDetector(
                           onTap: () {
-                            String url =
-                                'https://www.voitrans.net/doc/user_agreement.html';
-                            if (Get.locale?.languageCode != 'zh' ||
-                                Get.locale?.countryCode != 'CN') {
-                              url =
-                                  'https://www.voitrans.net/doc/user_agreement_en.html';
-                            }
                             Get.to(() => WebViewPage(
-                                  url: url,
+                                  url: userAgreementUrl(),
                                   title: 'userAgreement'.tr, // 用户协议
                                 ));
                           },

lib/modules/login/views/login_view.dart

@@ -4,6 +4,7 @@ import 'package:flutter_screenutil/flutter_screenutil.dart';
 import 'package:font_awesome_flutter/font_awesome_flutter.dart';
 import '../controllers/login_controller.dart';
 import '../../common/webview_page.dart';
+import '../../../core/utils/doc_url_helper.dart';
 
 class LoginView extends GetView<LoginController> {
   const LoginView({Key? key}) : super(key: key);
@@ -596,13 +597,8 @@ class LoginView extends GetView<LoginController> {
           children: [
             GestureDetector(
               onTap: () {
-                String url = 'https://www.voitrans.net/doc/user_agreement.html';
-                if (Get.locale?.languageCode != 'zh' ||
-                    Get.locale?.countryCode != 'CN') {
-                  url = 'https://www.voitrans.net/doc/user_agreement_en.html';
-                }
                 Get.to(() => WebViewPage(
-                      url: url,
+                      url: userAgreementUrl(),
                       title: 'userAgreement'.tr,
                     ));
               },
@@ -623,14 +619,8 @@ class LoginView extends GetView<LoginController> {
             ),
             GestureDetector(
               onTap: () {
-                String url = 'https://www.voitrans.net/doc/privacy_policy.html';
-                if (Get.locale?.languageCode != 'zh' ||
-                    Get.locale?.countryCode != 'CN') {
-                  url = 'https://www.voitrans.net/doc/privacy_policy_en.html';
-                }
-
                 Get.to(() => WebViewPage(
-                      url: url,
+                      url: privacyPolicyUrl(),
                       title: 'privacyPolicy'.tr,
                     ));
               },

lib/modules/profile/views/profile_view.dart

@@ -7,6 +7,7 @@ import '../../../routes/app_routes.dart';
 import 'dart:io';
 import 'dart:ui';
 import '../../common/webview_page.dart';
+import '../../../core/utils/doc_url_helper.dart';
 import 'unified_avatar.dart';
 
 // ProfileView: 用户设置页面
@@ -695,15 +696,8 @@ class EditProfileView extends GetView<ProfileController> {
                         isDarkMode ? Colors.purple[300]! : Colors.purple[600]!,
                     titleColor: isDarkMode ? Colors.white : Colors.black87,
                     onTap: () {
-                      String url =
-                          'https://www.voitrans.net/doc/user_agreement.html';
-                      if (Get.locale?.languageCode != 'zh' ||
-                          Get.locale?.countryCode != 'CN') {
-                        url =
-                            'https://www.voitrans.net/doc/user_agreement_en.html';
-                      }
                       Get.to(() => WebViewPage(
-                            url: url,
+                            url: userAgreementUrl(),
                             title: 'userAgreement'.tr,
                           ));
                     },
@@ -726,15 +720,8 @@ class EditProfileView extends GetView<ProfileController> {
                         isDarkMode ? Colors.purple[300]! : Colors.purple[600]!,
                     titleColor: isDarkMode ? Colors.white : Colors.black87,
                     onTap: () {
-                      String url =
-                          'https://www.voitrans.net/doc/privacy_policy.html';
-                      if (Get.locale?.languageCode != 'zh' ||
-                          Get.locale?.countryCode != 'CN') {
-                        url =
-                            'https://www.voitrans.net/doc/privacy_policy_en.html';
-                      }
                       Get.to(() => WebViewPage(
-                            url: url,
+                            url: privacyPolicyUrl(),
                             title: 'privacyPolicy'.tr,
                           ));
                     },