feat: add AI retouch and album preview actions

suixinkan/Features/TravelAlbum/Models/TravelAlbumPreviewModels.swift

@@ -84,10 +84,10 @@ struct TravelAlbumPreviewProject: Identifiable, Sendable, Hashable {
         assets.first { $0.kind == kind }
     }
 
-    /// 将当前素材映射为仅含原图的预览项目；新接口接入后替换此适配层即可。
+    /// 将素材映射为原图及实际存在的 AI 精修、氛围感结果图。
     init(material: TravelAlbumMaterial) {
         originalMaterialId = material.id
-        assets = [
+        var mappedAssets = [
             TravelAlbumPreviewAsset(
                 id: "original-\(material.id)",
                 kind: .original,
@@ -97,6 +97,33 @@ struct TravelAlbumPreviewProject: Identifiable, Sendable, Hashable {
                 fileSize: material.fileSize
             ),
         ]
+        let refinedURL = material.aiRefinedURL.trimmingCharacters(in: .whitespacesAndNewlines)
+        if !refinedURL.isEmpty {
+            mappedAssets.append(
+                TravelAlbumPreviewAsset(
+                    id: "retouched-\(material.id)",
+                    kind: .retouched,
+                    fileURL: refinedURL,
+                    coverURL: refinedURL,
+                    fileName: material.fileName,
+                    fileSize: material.fileSize
+                )
+            )
+        }
+        let atmosphereURL = material.aiAtmosphereURL.trimmingCharacters(in: .whitespacesAndNewlines)
+        if !atmosphereURL.isEmpty {
+            mappedAssets.append(
+                TravelAlbumPreviewAsset(
+                    id: "atmosphere-\(material.id)",
+                    kind: .atmosphere,
+                    fileURL: atmosphereURL,
+                    coverURL: atmosphereURL,
+                    fileName: material.fileName,
+                    fileSize: material.fileSize
+                )
+            )
+        }
+        assets = mappedAssets
     }
 
     /// 创建包含关联图片的项目，主要供适配器和测试使用。
@@ -142,6 +169,15 @@ enum TravelAlbumPreviewNavigator {
             $0.projectIndex == current.projectIndex - 1 && $0.kind == .original
         } ?? currentIndex - 1
     }
+
+    /// 返回删除当前项目后应展示的项目索引；优先保持原索引以显示下一张，末项则回退上一张。
+    static func projectIndexAfterDeletion(
+        deletedProjectIndex: Int,
+        remainingProjectCount: Int
+    ) -> Int? {
+        guard remainingProjectCount > 0 else { return nil }
+        return min(max(0, deletedProjectIndex), remainingProjectCount - 1)
+    }
 }
 
 /// 预览操作执行结果，便于后续替换真实业务接口。