feat: real-time wallet validation — key check, address display, USDC balance, claw402 health

- POST /api/wallet/validate: validate key, derive address, query Base USDC, check claw402
- Claw402ConfigForm: debounced validation, balance display, connection test button
- i18n: 11 new keys (en/zh/id)
- Private key never logged or stored

web/src/i18n/translations.ts

@@ -1230,6 +1230,17 @@ export const translations = {
       getApiKey: 'Get API Key',
       walletPrivateKeyLabel: 'Wallet Private Key *',
       selectModelLabel: 'Select Model',
+      validating: 'Validating...',
+      walletAddress: 'Wallet Address',
+      usdcBalance: 'Base USDC Balance',
+      claw402Connected: 'claw402 Connected',
+      claw402Unreachable: 'claw402 Unreachable',
+      depositUsdc: 'Deposit USDC to this address on Base chain',
+      invalidKeyPrefix: 'Please add 0x at the beginning',
+      invalidKeyLength: 'Should be 66 characters, currently',
+      invalidKeyChars: 'Contains invalid characters',
+      testConnection: 'Test Connection',
+      testingConnection: 'Testing...',
     },
 
     // ExchangeConfigModal
@@ -2508,6 +2519,17 @@ export const translations = {
       getApiKey: '获取 API Key',
       walletPrivateKeyLabel: '钱包私钥 *',
       selectModelLabel: '选择模型',
+      validating: '验证中...',
+      walletAddress: '钱包地址',
+      usdcBalance: 'Base USDC 余额',
+      claw402Connected: 'claw402 已连接',
+      claw402Unreachable: 'claw402 不可达',
+      depositUsdc: '请往此地址充值 Base 链 USDC',
+      invalidKeyPrefix: '请在开头加 0x',
+      invalidKeyLength: '应为 66 个字符，当前',
+      invalidKeyChars: '包含非法字符',
+      testConnection: '测试连接',
+      testingConnection: '测试中...',
     },
 
     exchangeConfig: {
@@ -3591,6 +3613,17 @@ export const translations = {
       getApiKey: 'Dapatkan API Key',
       walletPrivateKeyLabel: 'Private Key Wallet *',
       selectModelLabel: 'Pilih Model',
+      validating: 'Memvalidasi...',
+      walletAddress: 'Alamat Wallet',
+      usdcBalance: 'Saldo Base USDC',
+      claw402Connected: 'claw402 Terhubung',
+      claw402Unreachable: 'claw402 Tidak Dapat Dijangkau',
+      depositUsdc: 'Deposit USDC ke alamat ini di Base chain',
+      invalidKeyPrefix: 'Tambahkan 0x di awal',
+      invalidKeyLength: 'Harus 66 karakter, saat ini',
+      invalidKeyChars: 'Mengandung karakter tidak valid',
+      testConnection: 'Tes Koneksi',
+      testingConnection: 'Menguji...',
     },
 
     exchangeConfig: {