feat: 媒体库 blob 去重存储与品牌/注册等前端调整

新增：
- blob_store 二进制去重存储 + blob_dedup 测试

其它：
- 后端 settings/auth/media_library/upload/operations 服务与 handler 调整
- 前端品牌（BrandLockup/BrandCropModal/BrandSeoPanel）、注册、媒体库、分析详情页、Header/SiteChrome 等更新

backend/service/brand.go

@@ -9,16 +9,17 @@ import (
 
 // 站点品牌与页脚（公开设置，缺省为空）
 const (
-	SettingKeySiteWordmark  = "site_wordmark"
-	SettingKeySiteSlogan    = "site_slogan"
-	SettingKeySiteKeywords  = "site_keywords"
-	SettingKeyLogoLightURL  = "logo_light_url"
-	SettingKeyLogoDarkURL   = "logo_dark_url"
-	SettingKeyFaviconURL    = "favicon_url"
-	SettingKeyFooterLinks   = "footer_links"
-	SettingKeyBrandMark     = "brand_mark"
-	SettingKeyBrandLogoSize = "brand_logo_size"
-	SettingKeyBrandLogoFit  = "brand_logo_fit"
+	SettingKeySiteWordmark       = "site_wordmark"
+	SettingKeySiteSlogan         = "site_slogan"
+	SettingKeySiteKeywords       = "site_keywords"
+	SettingKeyLogoLightURL       = "logo_light_url"
+	SettingKeyLogoDarkURL        = "logo_dark_url"
+	SettingKeyFaviconURL         = "favicon_url"
+	SettingKeyFooterLinks        = "footer_links"
+	SettingKeyBrandMark          = "brand_mark"
+	SettingKeyBrandLogoSize      = "brand_logo_size"
+	SettingKeyBrandLogoFit       = "brand_logo_fit"
+	SettingKeyBrandSloganVisible = "brand_slogan_visible"
 
 	BrandSlotLight   = "logo_light"
 	BrandSlotDark    = "logo_dark"
@@ -43,6 +44,8 @@ const (
 	BrandLogoSize3x1 = "3x1"
 	BrandLogoSize4x1 = "4x1"
 	BrandLogoSize169 = "16x9"
+	// BrandLogoSizeAuto 原图比例：自由裁剪，页眉图槽按图片原始比例自适应宽度
+	BrandLogoSizeAuto = "auto"
 
 	BrandLogoFitCover   = "cover"
 	BrandLogoFitContain = "contain"
@@ -114,7 +117,7 @@ func NormalizeBrandLogoSize(raw string) (string, bool) {
 	switch strings.TrimSpace(raw) {
 	case "", BrandLogoSizeSQ:
 		return BrandLogoSizeSQ, true
-	case BrandLogoSize2x1, BrandLogoSize3x1, BrandLogoSize4x1, BrandLogoSize169:
+	case BrandLogoSize2x1, BrandLogoSize3x1, BrandLogoSize4x1, BrandLogoSize169, BrandLogoSizeAuto:
 		return strings.TrimSpace(raw), true
 	default:
 		return "", false
@@ -367,6 +370,15 @@ func (s *SettingService) fillBrand(out *PublicSiteSettings) error {
 			out.BrandLogoFit = f
 		}
 	}
+	sv, found, err := s.getValue(SettingKeyBrandSloganVisible)
+	if err != nil {
+		return err
+	}
+	if found {
+		out.BrandSloganVisible = sv == "true"
+	} else {
+		out.BrandSloganVisible = true
+	}
 	rawLinks, found, err := s.getValue(SettingKeyFooterLinks)
 	if err != nil {
 		return err
@@ -483,6 +495,14 @@ func (s *SettingService) SetBrandLogoFit(raw string) error {
 	return s.putValue(SettingKeyBrandLogoFit, v)
 }
 
+// SetBrandSloganVisible 控制标语是否在页眉显示；true 为缺省值，存库时删 key 以保持精简。
+func (s *SettingService) SetBrandSloganVisible(visible bool) error {
+	if visible {
+		return s.deleteKey(SettingKeyBrandSloganVisible)
+	}
+	return s.putValue(SettingKeyBrandSloganVisible, "false")
+}
+
 func (s *SettingService) setBrandURL(key, slot, url string) error {
 	u, ok := NormalizeBrandURL(slot, url)
 	if !ok {