refactor(goods): 移除预览功能并优化水印处理逻辑

- 移除了 sourceGoodsListPreview 接口及相关实现
- 新增 WatermarkEdgeService 和 FaceService 依赖注入
- 实现边缘端水印处理支持，包含降级机制
- 优化二维码和头像文件处理流程
- 统一水印处理的异常处理和资源清理逻辑

src/main/java/com/ycwl/basic/controller/mobile/AppGoodsController.java

@@ -53,12 +53,6 @@ public class AppGoodsController {
         return ApiResponse.success(count);
     }
 
-    @PostMapping("/sourceGoodsList/preview")
-    public ApiResponse<List<GoodsUrlVO>> sourceGoodsListPreview(@RequestBody GoodsReqQuery query) {
-        List<GoodsUrlVO> goodsUrlList = goodsService.sourceGoodsListPreview(query);
-        return ApiResponse.success(goodsUrlList);
-    }
-
     @PostMapping("/sourceGoodsList/download")
     public ApiResponse<List<GoodsUrlVO>> sourceGoodsListDownload(@RequestBody GoodsReqQuery query) {
         List<GoodsUrlVO> goodsUrlList = goodsService.sourceGoodsListDownload(query);