fix(android): 添加交易记录保存的错误处理

修复问题：
- saveTransactionRecord() 调用没有错误处理，保存失败会静默
- 如果保存失败，交易已广播但没有本地记录

改进：
- 添加 try-catch 捕获保存异常
- 保存失败时提示用户"交易已广播但保存记录失败"
- 添加成功日志便于调试

影响：
- 确保本地发起的交易 100% 被记录或提示失败原因

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

backend/mpc-system/services/service-party-android/app/src/main/java/com/durian/tssparty/presentation/viewmodel/MainViewModel.kt

@@ -1471,20 +1471,26 @@ class MainViewModel @Inject constructor(
                     // 保存交易记录到本地数据库
                     val state = _transferState.value
                     android.util.Log.d("MainViewModel", "[BROADCAST] Saving transaction record: shareId=${state.shareId}, tokenType=${state.tokenType}")
-                    repository.saveTransactionRecord(
-                        shareId = state.shareId,
-                        fromAddress = tx.from,
-                        toAddress = tx.to,
-                        amount = state.amount,
-                        tokenType = state.tokenType,
-                        txHash = hash,
-                        gasPrice = tx.gasPrice.toString()
-                    )
+                    try {
+                        repository.saveTransactionRecord(
+                            shareId = state.shareId,
+                            fromAddress = tx.from,
+                            toAddress = tx.to,
+                            amount = state.amount,
+                            tokenType = state.tokenType,
+                            txHash = hash,
+                            gasPrice = tx.gasPrice.toString()
+                        )
+                        android.util.Log.d("MainViewModel", "[BROADCAST] Transaction record saved successfully")
 
-                    // 启动后台确认交易状态
-                    confirmTransactionInBackground(hash, rpcUrl)
+                        // 启动后台确认交易状态
+                        confirmTransactionInBackground(hash, rpcUrl)
 
-                    _uiState.update { it.copy(isLoading = false, successMessage = "交易已广播!") }
+                        _uiState.update { it.copy(isLoading = false, successMessage = "交易已广播!") }
+                    } catch (e: Exception) {
+                        android.util.Log.e("MainViewModel", "[BROADCAST] Failed to save transaction record: ${e.message}", e)
+                        _uiState.update { it.copy(isLoading = false, error = "交易已广播但保存记录失败: ${e.message}") }
+                    }
                 },
                 onFailure = { e ->
                     android.util.Log.e("MainViewModel", "[BROADCAST] FAILED: ${e.message}", e)