fix: 优化收款码加载态，避免首屏错误占位闪现

Co-authored-by: Cursor <cursoragent@cursor.com>

suixinkan/Features/Payment/ViewModels/PaymentCollectionDetailsViewModel.swift

@@ -28,6 +28,7 @@ final class PaymentCollectionDetailsViewModel {
 
     private var staticPayURL = ""
     private var dynamicPayURL = ""
+    private var hasCompletedPayCodeRequest = false
     private let appStore: AppStore
     private let payPageConfigCache: PayPageConfigCaching
 
@@ -50,6 +51,11 @@ final class PaymentCollectionDetailsViewModel {
         qrImage != nil && !staticPayURL.isEmpty
     }
 
+    /// 是否应在二维码区域展示加载状态，首次请求开始前也视为加载中，避免短暂闪现错误占位。
+    var isPayCodeLoading: Bool {
+        loading || !hasCompletedPayCodeRequest
+    }
+
     var displayScenicName: String {
         scenicName.isEmpty ? "暂无景区" : scenicName
     }
@@ -85,11 +91,11 @@ final class PaymentCollectionDetailsViewModel {
 
     func loadPayCode(api: PaymentAPI) async {
         guard !loading else { return }
-        refreshLocalState()
         loading = true
-        notifyStateChange()
+        refreshLocalState()
         defer {
             loading = false
+            hasCompletedPayCodeRequest = true
             notifyStateChange()
         }