🐛 Tried to fix fund claim cocurrency issue

DysonNetwork.Pass/Wallet/PaymentService.cs

@@ -609,6 +609,12 @@ public class PaymentService(
 
     public async Task<SnWalletTransaction> ReceiveFundAsync(Guid recipientAccountId, Guid fundId)
     {
+        // Use a transaction to ensure atomicity
+        await using var transactionScope = await db.Database.BeginTransactionAsync();
+
+        try
+        {
+            // Load fund with proper locking to prevent concurrent modifications
             var fund = await db.WalletFunds
                 .Include(f => f.Recipients)
                 .FirstOrDefaultAsync(f => f.Id == fundId);
@@ -668,7 +674,7 @@ public class PaymentService(
                 throw new InvalidOperationException("Recipient wallet not found");
 
             // Create transaction to transfer funds to recipient
-        var transaction = await CreateTransactionAsync(
+            var walletTransaction = await CreateTransactionAsync(
                 payerWalletId: null, // System transfer
                 payeeWalletId: recipientWallet.Id,
                 currency: fund.Currency,
@@ -700,8 +706,15 @@ public class PaymentService(
             }
 
             await db.SaveChangesAsync();
+            await transactionScope.CommitAsync();
 
-        return transaction;
+            return walletTransaction;
+        }
+        catch
+        {
+            await transactionScope.RollbackAsync();
+            throw;
+        }
     }
 
     public async Task ProcessExpiredFundsAsync()