新增首页 AW炫彩回收入口，支持后台配置展示图

首页第三入口点击查看回收说明图；配置项 mobile.aw_recycle 可配标题/图片；aw-recycle 走公开文件链路，首页鉴权预览兼容旧私有地址。

backend/internal/modules/systemconfig/repository.go

@@ -45,6 +45,7 @@ var defaultConfigs = []defaultConfig{
 	{Key: "integration.paddle_ocr_model", Value: "PaddleOCR-VL-1.6", Description: "PaddleOCR 识别模型"},
 	{Key: homeAnnouncementsConfigKey, Value: defaultHomeAnnouncementsConfigValue(), Description: "移动端首页公告 JSON 数组"},
 	{Key: homeBannersConfigKey, Value: defaultHomeBannersConfigValue(), Description: "移动端首页轮播图 JSON 数组"},
+	{Key: awRecycleConfigKey, Value: defaultAWRecycleConfigValue(), Description: "首页 AW炫彩回收入口配置 JSON（标题/副标题/展示图片）"},
 	{Key: publishOptionsConfigKey, Value: defaultPublishOptionsConfigValue(), Description: "发布页选项配置 JSON"},
 	{Key: salePriceConfigKey, Value: defaultSalePriceConfigValue(), Description: "内部出售定价规则 JSON"},
 }
@@ -67,6 +68,7 @@ var adminVisibleConfigKeys = []string{
 	"listing.sale_price_config",
 	"mobile.home_announcements",
 	"mobile.home_banners",
+	"mobile.aw_recycle",
 	"order.agreements",
 	"order.pending_payment_timeout_minutes",
 	"order.return_overdue_grace_minutes",