Add instant payment collection flow aligned with Android.

Implement收款详情与收款记录 pages with pay-code API, QR generation, amount setting, and record grouping so merchants can collect payments from the home quick action.

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

suixinkan/Common/PhotoLibrarySaver.swift

@@ -0,0 +1,37 @@
+//
+//  PhotoLibrarySaver.swift
+//  suixinkan
+//
+
+import Photos
+import UIKit
+
+/// 将图片保存到系统相册，供收款二维码保存使用。
+enum PhotoLibrarySaver {
+
+    /// 请求写入权限并将图片保存到相册。
+    static func saveImage(_ image: UIImage) async -> Bool {
+        let status = await requestAuthorizationIfNeeded()
+        guard status == .authorized || status == .limited else {
+            return false
+        }
+
+        return await withCheckedContinuation { continuation in
+            PHPhotoLibrary.shared().performChanges({
+                PHAssetChangeRequest.creationRequestForAsset(from: image)
+            }, completionHandler: { success, _ in
+                continuation.resume(returning: success)
+            })
+        }
+    }
+
+    private static func requestAuthorizationIfNeeded() async -> PHAuthorizationStatus {
+        let current = PHPhotoLibrary.authorizationStatus(for: .addOnly)
+        switch current {
+        case .notDetermined:
+            return await PHPhotoLibrary.requestAuthorization(for: .addOnly)
+        default:
+            return current
+        }
+    }
+}