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/operations_storage.go

@@ -16,6 +16,8 @@ import (
 	"path/filepath"
 	"strings"
 	"time"
+
+	"gorm.io/gorm"
 )
 
 func (o *Operations) s3(c StorageConfig) (*minio.Client, error) {
@@ -137,6 +139,65 @@ func (o *Operations) StoreFile(path, mimeType string, public bool) (string, erro
 	}
 	return id, nil
 }
+
+// blobObjectID 内容寻址对象的稳定 ID：公开/私有加不同前缀，同字节也不共享可见性。
+func blobObjectID(hash string, public bool) string {
+	if public {
+		return "pub_" + hash
+	}
+	return "prv_" + hash
+}
+
+// StoreFileHashed 按内容 hash 幂等上传：同一 (hash, public) 只存一份，重复上传跳过传输。
+// 本地后端返回空 ID（文件留在本地 blob 目录，由调用方做引用计数）。
+func (o *Operations) StoreFileHashed(path, mimeType string, public bool, hash string) (string, error) {
+	v, version, e := o.read(o.db, "storage")
+	if e != nil {
+		return "", errors.New("读取存储配置失败")
+	}
+	c := *v.(*StorageConfig)
+	if c.Backend == "local" {
+		return "", nil
+	}
+	id := blobObjectID(hash, public)
+	// hash 相同字节必然相同：对象已存在时直接复用，省掉整次上传
+	var existing model.StoredObject
+	if e := o.db.First(&existing, "id = ?", id).Error; e == nil {
+		return id, nil
+	} else if !errors.Is(e, gorm.ErrRecordNotFound) {
+		return "", e
+	}
+	client, e := o.s3(c)
+	if e != nil {
+		return "", e
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
+	defer cancel()
+	f, e := os.Open(path)
+	if e != nil {
+		return "", e
+	}
+	stat, e := f.Stat()
+	if e != nil {
+		_ = f.Close()
+		return "", e
+	}
+	key := c.Prefix + "objects/" + id
+	if _, e = client.PutObject(ctx, c.Bucket, key, f, stat.Size(), minio.PutObjectOptions{ContentType: mimeType, DisableMultipart: true}); e != nil {
+		_ = f.Close()
+		return "", errors.New("上传到 S3 失败，当前目标未自动切换")
+	}
+	_ = f.Close()
+	obj := model.StoredObject{ID: id, ConfigName: fmt.Sprintf("storage-%d", version), Key: key, MIME: mimeType, Public: public}
+	if e = o.db.Create(&obj).Error; e != nil {
+		if isUniqueConflict(e) { // 并发：另一请求已写入同内容对象，直接复用
+			return id, nil
+		}
+		_ = client.RemoveObject(ctx, c.Bucket, key, minio.RemoveObjectOptions{})
+		return "", errors.New("保存文件记录失败")
+	}
+	return id, nil
+}
 func (o *Operations) OpenObject(ctx context.Context, id string, requirePublic bool) (io.ReadCloser, string, error) {
 	var obj model.StoredObject
 	if e := o.db.First(&obj, "id = ?", id).Error; e != nil {