Fix: Add confirmations support and fix notification logic

Webhook Improvements:
- Added Confirmations field to PaymentWebhookDto (default: 0)
- Updated webhook controller to pass confirmations to service layer
- Fixed notification logic to match order update conditions

Payment Confirmation Logic:
- Paid (2): Confirmed immediately regardless of confirmations
- Overpaid (3): Confirmed immediately regardless of confirmations
- Completed (7): Requires 3+ blockchain confirmations
- Notifications only sent when order is actually updated

This prevents premature notifications for unconfirmed 'Completed' status
while maintaining immediate processing for 'Paid' and 'Overpaid' statuses.

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

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

LittleShop/Controllers/OrdersController.cs

@@ -175,10 +175,11 @@ public class OrdersController : ControllerBase
     public async Task<ActionResult> PaymentWebhook([FromBody] PaymentWebhookDto webhookDto)
     {
         var success = await _cryptoPaymentService.ProcessPaymentWebhookAsync(
-            webhookDto.InvoiceId, 
-            webhookDto.Status, 
-            webhookDto.Amount, 
-            webhookDto.TransactionHash);
+            webhookDto.InvoiceId,
+            webhookDto.Status,
+            webhookDto.Amount,
+            webhookDto.TransactionHash,
+            webhookDto.Confirmations);
 
         if (!success)
         {
@@ -205,4 +206,5 @@ public class PaymentWebhookDto
     public PaymentStatus Status { get; set; }
     public decimal Amount { get; set; }
     public string? TransactionHash { get; set; }
+    public int Confirmations { get; set; } = 0;
 }