fix(mobile): fix version check API and platform detection in both apps

genex-mobile/lib/core/updater/version_checker.dart
- platform 从写死 'android' 改为运行时检测 Platform.isIOS ? 'IOS' : 'ANDROID'

admin-app/lib/core/updater/version_checker.dart
- API 路径修正: /api/app/version/check → /api/v1/app/version/check
- 新增 app_type: 'ADMIN_APP'（原缺失，后端默认返回 GENEX_MOBILE 版本）
- platform 从写死 'android' 改为运行时检测
- 响应解析修正: 原逻辑把外层 {code,data} 当版本数据用，
  改为正确取 response.data['data'] 内层对象
- 新增 downloadUrl 相对路径修复（向下兼容旧记录）

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/admin-app/lib/core/updater/version_checker.dart

@@ -1,6 +1,7 @@
 import 'package:package_info_plus/package_info_plus.dart';
 import 'package:dio/dio.dart';
 import 'package:flutter/foundation.dart';
+import 'dart:io' show Platform;
 import 'models/version_info.dart';
 
 /// 版本检测器
@@ -27,26 +28,34 @@ class VersionChecker {
       final currentInfo = await getCurrentVersion();
       debugPrint('[VersionChecker] 当前版本: ${currentInfo.version}, buildNumber: ${currentInfo.buildNumber}');
 
+      final platform = Platform.isIOS ? 'IOS' : 'ANDROID';
       final response = await _dio.get(
-        '/api/app/version/check',
+        '/api/v1/app/version/check',
         queryParameters: {
-          'platform': 'android',
+          'app_type': 'ADMIN_APP',
+          'platform': platform,
           'current_version': currentInfo.version,
           'current_version_code': currentInfo.buildNumber,
         },
       );
 
       if (response.statusCode == 200 && response.data != null) {
-        final data = response.data is Map<String, dynamic>
-            ? response.data as Map<String, dynamic>
-            : (response.data['data'] as Map<String, dynamic>?) ?? response.data;
+        final responseMap = response.data as Map<String, dynamic>;
+        final data = (responseMap['data'] as Map<String, dynamic>?) ?? responseMap;
 
-        final needUpdate = data['needUpdate'] as bool? ?? true;
+        final needUpdate = data['needUpdate'] as bool? ?? false;
         if (!needUpdate) {
           debugPrint('[VersionChecker] 无需更新');
           return null;
         }
-        return VersionInfo.fromJson(data);
+
+        // Fix relative downloadUrl → prepend apiBaseUrl for backward compatibility
+        final rawUrl = data['downloadUrl'] as String? ?? '';
+        final fixedData = (rawUrl.isNotEmpty && !rawUrl.startsWith('http'))
+            ? (Map<String, dynamic>.from(data)..['downloadUrl'] = '$apiBaseUrl$rawUrl')
+            : data;
+
+        return VersionInfo.fromJson(fixedData);
       }
       return null;
     } catch (e) {

frontend/genex-mobile/lib/core/updater/version_checker.dart

@@ -1,6 +1,7 @@
 import 'package:package_info_plus/package_info_plus.dart';
 import 'package:dio/dio.dart';
 import 'package:flutter/foundation.dart';
+import 'dart:io' show Platform;
 import 'models/version_info.dart';
 
 /// 版本检测器
@@ -27,11 +28,12 @@ class VersionChecker {
       final currentInfo = await getCurrentVersion();
       debugPrint('[VersionChecker] 当前版本: ${currentInfo.version}, buildNumber: ${currentInfo.buildNumber}');
 
+      final platform = Platform.isIOS ? 'IOS' : 'ANDROID';
       final response = await _dio.get(
         '/api/v1/app/version/check',
         queryParameters: {
           'app_type': 'GENEX_MOBILE',
-          'platform': 'android',
+          'platform': platform,
           'current_version': currentInfo.version,
           'current_version_code': currentInfo.buildNumber,
         },