fix(mobile-app): skip backup mnemonic page for MPC wallet mode

- Fix mnemonic parsing: empty string "" now correctly becomes empty list
- MPC mode (no mnemonic) skips backup page and navigates directly to home
- Apply fix to both initial load and polling logic

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.claude/settings.local.json

@@ -41,7 +41,8 @@
       "Bash(git -C \"c:\\Users\\dong\\Desktop\\rwadurian\" commit -m \"$(cat <<''EOF''\nfix(identity): update migration to TEXT avatar and remove province/city/address\n\n- Change avatar_url column from VARCHAR(500) to TEXT\n- Remove province_code, city_code, address columns from user_accounts\n- Remove idx_province_city index\n\n🤖 Generated with [Claude Code](https://claude.com/claude-code)\n\nCo-Authored-By: Claude <noreply@anthropic.com>\nEOF\n)\")",
       "Bash(git -C \"c:\\Users\\dong\\Desktop\\rwadurian\" commit -m \"$(cat <<''EOF''\nfix(identity): remove address from updateProfile and fix deviceInfo type\n\n- Remove dto.address parameter from updateProfile controller\n- Remove address property from updateProfile service\n- Fix deviceInfo JSON serialization for Prisma InputJsonValue type\n\n🤖 Generated with [Claude Code](https://claude.com/claude-code)\n\nCo-Authored-By: Claude <noreply@anthropic.com>\nEOF\n)\")",
       "Bash(git -C \"c:\\Users\\dong\\Desktop\\rwadurian\" checkout -- backend/services/identity-service/prisma/migrations/20241204000000_init/migration.sql)",
-      "Bash(git -C \"c:\\Users\\dong\\Desktop\\rwadurian\" commit -m \"$(cat <<''EOF''\nfix(identity): add device_info columns to user_devices migration\n\n- Add device_info JSONB column for storing complete device info\n- Add platform, device_model, os_version, app_version columns\n- Add screen_width, screen_height, locale, timezone columns\n- Add idx_platform index\n\n🤖 Generated with [Claude Code](https://claude.com/claude-code)\n\nCo-Authored-By: Claude <noreply@anthropic.com>\nEOF\n)\")"
+      "Bash(git -C \"c:\\Users\\dong\\Desktop\\rwadurian\" commit -m \"$(cat <<''EOF''\nfix(identity): add device_info columns to user_devices migration\n\n- Add device_info JSONB column for storing complete device info\n- Add platform, device_model, os_version, app_version columns\n- Add screen_width, screen_height, locale, timezone columns\n- Add idx_platform index\n\n🤖 Generated with [Claude Code](https://claude.com/claude-code)\n\nCo-Authored-By: Claude <noreply@anthropic.com>\nEOF\n)\")",
+      "Bash(git -C \"c:\\Users\\dong\\Desktop\\rwadurian\" commit -m \"$(cat <<''EOF''\nfix(mobile-app): fix API response parsing for auto-create and wallet\n\n- Extract ''data'' field from API response before parsing\n- Fix createAccount() to parse responseData[''data'']\n- Fix getWalletInfo() to parse responseData[''data'']\n- Resolves: type ''Null'' is not a subtype of type ''int'' in type cast\n\n🤖 Generated with [Claude Code](https://claude.com/claude-code)\n\nCo-Authored-By: Claude <noreply@anthropic.com>\nEOF\n)\")"
     ],
     "deny": [],
     "ask": []

frontend/mobile-app/lib/features/auth/presentation/pages/backup_mnemonic_page.dart

@@ -89,14 +89,27 @@ class _BackupMnemonicPageState extends ConsumerState<BackupMnemonicPage> {
 
       if (response.isReady) {
         // 钱包已就绪
-        final wordCount = response.mnemonic?.split(' ').length ?? 0;
+        // 处理助记词：空字符串或null都视为无助记词（MPC模式）
+        final mnemonic = response.mnemonic?.trim() ?? '';
+        final words = mnemonic.isEmpty ? <String>[] : mnemonic.split(' ');
+        final wordCount = words.length;
         debugPrint('[BackupMnemonicPage] _loadWalletInfo - 钱包就绪! 助记词数量: $wordCount');
         debugPrint('[BackupMnemonicPage] _loadWalletInfo - KAVA: ${_maskAddress(response.walletAddresses?.kava)}');
         debugPrint('[BackupMnemonicPage] _loadWalletInfo - DST: ${_maskAddress(response.walletAddresses?.dst)}');
         debugPrint('[BackupMnemonicPage] _loadWalletInfo - BSC: ${_maskAddress(response.walletAddresses?.bsc)}');
+
+        // MPC模式：无助记词，直接跳转到主页
+        if (wordCount == 0) {
+          debugPrint('[BackupMnemonicPage] _loadWalletInfo - MPC模式，无助记词，跳转到主页');
+          if (mounted) {
+            context.go('/home');
+          }
+          return;
+        }
+
         setState(() {
           _walletInfo = response;
-          _mnemonicWords = response.mnemonic?.split(' ') ?? [];
+          _mnemonicWords = words;
           _kavaAddress = response.walletAddresses?.kava;
           _dstAddress = response.walletAddresses?.dst;
           _bscAddress = response.walletAddresses?.bsc;
@@ -197,11 +210,24 @@ class _BackupMnemonicPageState extends ConsumerState<BackupMnemonicPage> {
           debugPrint('[BackupMnemonicPage] _startPolling - 钱包就绪! 停止轮询 (共轮询 $_pollCount 次)');
           timer.cancel();
           _stopCountdown();
-          final wordCount = response.mnemonic?.split(' ').length ?? 0;
+          // 处理助记词：空字符串或null都视为无助记词（MPC模式）
+          final mnemonic = response.mnemonic?.trim() ?? '';
+          final words = mnemonic.isEmpty ? <String>[] : mnemonic.split(' ');
+          final wordCount = words.length;
           debugPrint('[BackupMnemonicPage] _startPolling - 助记词数量: $wordCount');
+
+          // MPC模式：无助记词，直接跳转到主页
+          if (wordCount == 0) {
+            debugPrint('[BackupMnemonicPage] _startPolling - MPC模式，无助记词，跳转到主页');
+            if (mounted) {
+              context.go('/home');
+            }
+            return;
+          }
+
           setState(() {
             _walletInfo = response;
-            _mnemonicWords = response.mnemonic?.split(' ') ?? [];
+            _mnemonicWords = words;
             _kavaAddress = response.walletAddresses?.kava;
             _dstAddress = response.walletAddresses?.dst;
             _bscAddress = response.walletAddresses?.bsc;