feat(listings): 排序交互升级为双向翻转并对齐双端体验

- PC端交互：HomeView 排序按钮支持点击切换升降序翻转（比例、哈夫币、AWM数量、合并价格为单个价格项），并带有高低方向箭头（▲/▼）高亮指示
- 移动端交互：MobileHomeView 菜单提供清晰的双向文案（如「比例从高到低 / 比例从低到高」），且点击当前选中项时支持自动翻转方向，顶部工具栏标题紧凑对齐
- 后端排序：public_filter 与 public_query 完整支持 ratioDesc/ratioAsc、priceAsc/priceDesc、coinDesc/coinAsc、awmDesc/awmAsc
- 验证方式：新增并运行 TestSortPublicListingsByRatio 包含升序/降序多断言，全量运行 ./scripts/check.sh 门禁全绿通过

backend/internal/modules/listing/public_query.go

@@ -146,7 +146,7 @@ func canListPublicWithSQL(query PublicListQuery) bool {
 		return false
 	}
 	switch query.Sort {
-	case "", "published", "recommended", "comprehensive", "priceAsc", "priceDesc", "coinDesc":
+	case "", "published", "recommended", "comprehensive", "priceAsc", "priceDesc", "coinDesc", "coinAsc":
 		return true
 	default:
 		return false
@@ -161,6 +161,8 @@ func applyPublicSQLSort(db *gorm.DB, sortKey string) *gorm.DB {
 		return db.Order("l.price_cent DESC, l.published_at DESC, l.id DESC")
 	case "coinDesc":
 		return db.Order("a.haf_coin_amount DESC, l.published_at DESC, l.id DESC")
+	case "coinAsc":
+		return db.Order("a.haf_coin_amount ASC, l.published_at DESC, l.id DESC")
 	case "published":
 		return db.Order("l.published_at DESC, l.id DESC")
 	default: