对齐旅拍相册详情页 Android UI，并修复网格预览与布局问题。

重构相册详情为信息卡片、Tab 筛选、排序、批量删除与底部上传栏；修复网格重叠、禁用按钮蒙层，并支持点击预览大图。同步扩展素材列表 API 与 ViewModel 分页逻辑，并优化有线传图缩略图与传输性能。

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

suixinkan/Core/CameraTethering/Storage/CameraDownloadStorage.swift

@@ -6,6 +6,8 @@
 //
 
 import Foundation
+import ImageIO
+import UniformTypeIdentifiers
 
 /// 相机下载文件本地存储工具，负责目录创建、相对路径持久化与安全文件名处理。
 enum CameraDownloadStorage {
@@ -23,9 +25,21 @@ enum CameraDownloadStorage {
         return directory
     }
 
+    /// 相机照片列表缩略图目录。
+    static var thumbnailsDirectory: URL {
+        let directory = downloadsDirectory.appendingPathComponent("Thumbnails", isDirectory: true)
+        try? FileManager.default.createDirectory(at: directory, withIntermediateDirectories: true)
+        return directory
+    }
+
     /// 将绝对路径转为相对 Documents 的路径，如 `CameraDownloads/1730_DSC.JPG`。
     static func relativePath(for url: URL) -> String {
-        "\(cameraDownloadsFolderName)/\(url.lastPathComponent)"
+        let standardizedURL = url.standardizedFileURL
+        let thumbnailsPath = thumbnailsDirectory.standardizedFileURL.path
+        if standardizedURL.path.hasPrefix(thumbnailsPath) {
+            return "\(cameraDownloadsFolderName)/Thumbnails/\(url.lastPathComponent)"
+        }
+        return "\(cameraDownloadsFolderName)/\(url.lastPathComponent)"
     }
 
     /// 将持久化的相对或旧版绝对路径解析为当前沙盒内的文件 URL。
@@ -82,6 +96,13 @@ enum CameraDownloadStorage {
         return downloadsDirectory.appendingPathComponent("\(timestamp)_\(safeName)")
     }
 
+    /// 生成带 asset ID 的唯一缩略图文件 URL。
+    static func uniqueThumbnailURL(for assetID: String) -> URL {
+        let safeName = sanitizeFilename(assetID)
+            .replacingOccurrences(of: ".", with: "_")
+        return thumbnailsDirectory.appendingPathComponent("\(safeName)_thumb.jpg")
+    }
+
     /// 将相机 PTP 文件名转为 iOS 文件系统可安全使用的 ASCII 名称。
     static func sanitizeFilename(_ filename: String) -> String {
         let trimmed = filename
@@ -111,4 +132,57 @@ enum CameraDownloadStorage {
         }
         return url.absoluteString
     }
+
+    /// 后台读取文件大小，避免在列表刷新路径上阻塞主线程。
+    static func fileSizeBytes(for url: URL?) async -> Int64 {
+        guard let url else { return 0 }
+        return await Task.detached(priority: .utility) {
+            (try? FileManager.default.attributesOfItem(atPath: url.path)[.size] as? Int64) ?? 0
+        }.value
+    }
+}
+
+/// 相机本地照片缩略图生成器，负责为列表生成小尺寸预览图。
+enum CameraThumbnailGenerator {
+    private static let maxPixelSize: CGFloat = 160
+
+    /// 为本地照片生成列表缩略图，成功时返回相对 Documents 的持久化路径。
+    static func generateThumbnail(for imageURL: URL, assetID: String) async -> String? {
+        await Task.detached(priority: .utility) {
+            guard FileManager.default.fileExists(atPath: imageURL.path),
+                  let source = CGImageSourceCreateWithURL(imageURL as CFURL, nil) else {
+                return nil
+            }
+
+            let options: [CFString: Any] = [
+                kCGImageSourceCreateThumbnailFromImageAlways: true,
+                kCGImageSourceShouldCacheImmediately: false,
+                kCGImageSourceCreateThumbnailWithTransform: true,
+                kCGImageSourceThumbnailMaxPixelSize: maxPixelSize
+            ]
+            guard let thumbnail = CGImageSourceCreateThumbnailAtIndex(source, 0, options as CFDictionary) else {
+                return nil
+            }
+
+            let destination = CameraDownloadStorage.uniqueThumbnailURL(for: assetID)
+            if FileManager.default.fileExists(atPath: destination.path) {
+                try? FileManager.default.removeItem(at: destination)
+            }
+            guard let imageDestination = CGImageDestinationCreateWithURL(
+                destination as CFURL,
+                UTType.jpeg.identifier as CFString,
+                1,
+                nil
+            ) else {
+                return nil
+            }
+
+            CGImageDestinationAddImage(imageDestination, thumbnail, [
+                kCGImageDestinationLossyCompressionQuality: 0.78
+            ] as CFDictionary)
+
+            guard CGImageDestinationFinalize(imageDestination) else { return nil }
+            return CameraDownloadStorage.relativePath(for: destination)
+        }.value
+    }
 }