feat: add AI retouch before-after comparison

suixinkan/Features/TravelAlbum/AI修图接口文档.md

@@ -117,6 +117,8 @@ GET /api/yf-handset-app/photog/travel-album/ai-retouch-options?user_equity_trave
             "id": "tpl_refined_12",
             "name": "清透精修",
             "preview_url": "https://cdn.example.com/templates/refined_12.jpg",
+            "before_url": "https://cdn.example.com/templates/refined_12_before.jpg",
+            "after_url": "https://cdn.example.com/templates/refined_12_after.jpg",
             "enabled": true
           }
         ]
@@ -135,6 +137,8 @@ GET /api/yf-handset-app/photog/travel-album/ai-retouch-options?user_equity_trave
             "id": "tpl_atmosphere_06",
             "name": "暖阳",
             "preview_url": "https://cdn.example.com/templates/atmosphere_06.jpg",
+            "before_url": "https://cdn.example.com/templates/atmosphere_06_before.jpg",
+            "after_url": "https://cdn.example.com/templates/atmosphere_06_after.jpg",
             "enabled": true
           }
         ]
@@ -153,6 +157,8 @@ GET /api/yf-handset-app/photog/travel-album/ai-retouch-options?user_equity_trave
             "id": "tpl_cover_03",
             "name": "旅行画册",
             "preview_url": "https://cdn.example.com/templates/cover_03.jpg",
+            "before_url": "https://cdn.example.com/templates/cover_03_before.jpg",
+            "after_url": "https://cdn.example.com/templates/cover_03_after.jpg",
             "enabled": true
           }
         ]
@@ -178,6 +184,7 @@ GET /api/yf-handset-app/photog/travel-album/ai-retouch-options?user_equity_trave
 
 - 不再让 App 传 `scenic_id`，后端从相册归属景区获取可用模板。
 - 由后端返回 `required` 和可见分组，避免多端各写一套“4 张显示封面”规则。
+- `preview_url` 用于模板卡片缩略图；`before_url` 与 `after_url` 必须是同尺寸、同构图的配对图片，供客户端滑动对比。
 - 客户端可默认选中必选分组的第一个可用模板，可选分组默认不选。
 - 此接口用于 UI 配置；提交时后端仍必须根据真实素材 ID 重新校验。
 - 同一响应返回当前用户的剩余可用额度和每类输出的额度单价，弹窗无需再发起第二个额度请求。