fix(checkout): display snackbar on top of sheet modals

pedi-foods/Sources/PediFoods/Views/Main/CheckoutView.swift

@@ -929,6 +929,7 @@ struct CardSelectionSheet: View {
     }
 
     var body: some View {
+        ZStack(alignment: .top) {
             VStack(spacing: 0) {
                 // Header
                 HStack {
@@ -1013,6 +1014,9 @@ struct CardSelectionSheet: View {
                     }
                 )
             }
+
+            SnackbarOverlay(center: SnackbarCenter.shared)
+        }
     }
 
     private func savedCardRow(_ card: SavedCard) -> some View {
@@ -1133,6 +1137,7 @@ struct PaymentCardView: View {
     }
 
     var body: some View {
+        ZStack(alignment: .top) {
             VStack(spacing: 0) {
                 HStack {
                     Text("Novo Cartão")
@@ -1163,6 +1168,7 @@ struct PaymentCardView: View {
                                 Text("Total do Pedido")
                                     .font(AppTypography.caption)
                                     .foregroundStyle(AppColors.textMuted)
+                                    .textCase(nil)
                                 Text(formatCurrency(context.total))
                                     .font(AppTypography.heading2)
                                     .foregroundStyle(AppColors.textPrimary)
@@ -1264,9 +1270,11 @@ struct PaymentCardView: View {
                     }
                     .padding(20)
                 }
+            }
             .background(AppColors.backgroundLight)
-        } // VStack
-        .background(AppColors.backgroundLight)
+
+            SnackbarOverlay(center: SnackbarCenter.shared)
+        }
     }
 
     @MainActor
@@ -1527,6 +1535,7 @@ struct ChangePaymentCardSheet: View {
     }
 
     var body: some View {
+        ZStack(alignment: .top) {
             VStack(spacing: 0) {
                 HStack {
                     Text("Cartão de Crédito").font(AppTypography.heading2).foregroundStyle(AppColors.textPrimary)
@@ -1590,6 +1599,9 @@ struct ChangePaymentCardSheet: View {
                     showNewCardForm = false; onConfirmed(orderId, shortId)
                 }
             }
+
+            SnackbarOverlay(center: SnackbarCenter.shared)
+        }
     }
 
     @MainActor
@@ -1688,6 +1700,7 @@ struct ChangePaymentNewCardView: View {
     }
 
     var body: some View {
+        ZStack(alignment: .top) {
             VStack(spacing: 0) {
                 HStack {
                     Text("Novo Cartão").font(AppTypography.heading2).foregroundStyle(AppColors.textPrimary)
@@ -1737,6 +1750,9 @@ struct ChangePaymentNewCardView: View {
                 }
             }
             .background(AppColors.backgroundLight)
+
+            SnackbarOverlay(center: SnackbarCenter.shared)
+        }
     }
 
     @MainActor