Migrate from iOS 17 Observation to iOS 16-compatible Combine architecture.

Lower deployment target to iOS 16, replace @Observable with ObservableObject, add navigation and UI compatibility shims, and include login smoke UI tests.

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

suixinkan/Features/Payment/ViewModels/PaymentViewModel.swift

@@ -8,25 +8,24 @@
 import CoreImage
 import CoreImage.CIFilterBuiltins
 import Foundation
-import Observation
+import Combine
 import UIKit
 
 @MainActor
-@Observable
 /// 收款页 ViewModel，管理收款码加载、动态金额二维码和到账轮询。
-final class PaymentCollectionViewModel {
-    var staticPayUrl = ""
-    var dynamicPayUrl = ""
-    var amountText = ""
-    var remarkText = ""
-    var currentPayUrl = ""
-    var qrImage: UIImage?
-    var isLoading = false
-    var isPolling = false
-    var errorMessage: String?
-    var status: PaymentCollectionStatus = .idle
+final class PaymentCollectionViewModel: ObservableObject {
+    @Published var staticPayUrl = ""
+    @Published var dynamicPayUrl = ""
+    @Published var amountText = ""
+    @Published var remarkText = ""
+    @Published var currentPayUrl = ""
+    @Published var qrImage: UIImage?
+    @Published var isLoading = false
+    @Published var isPolling = false
+    @Published var errorMessage: String?
+    @Published var status: PaymentCollectionStatus = .idle
 
-    private var knownRecordIDs = Set<String>()
+    @Published private var knownRecordIDs = Set<String>()
     private let context = CIContext()
     private let qrFilter = CIFilter.qrCodeGenerator()
 
@@ -191,12 +190,11 @@ private extension String {
 }
 
 @MainActor
-@Observable
 /// 收款记录 ViewModel，管理收款记录加载、日期分组和汇总兜底。
-final class PaymentCollectionRecordViewModel {
-    var groups: [PaymentCollectionRecordGroup] = []
-    var isLoading = false
-    var errorMessage: String?
+final class PaymentCollectionRecordViewModel: ObservableObject {
+    @Published var groups: [PaymentCollectionRecordGroup] = []
+    @Published var isLoading = false
+    @Published var errorMessage: String?
 
     /// 加载当前景区收款记录，无景区时不请求接口。
     func load(api: PaymentServing, scenicId: Int?) async {