feat: 支持移动端上传本地照片作为自定义头像，并允许公开读取头像

backend/internal/modules/file/handler.go

@@ -65,7 +65,7 @@ func (h *Handler) writeObject(c *gin.Context, publicOnly bool) {
 		response.BadRequest(c, "文件 key 不正确")
 		return
 	}
-	if publicOnly && !strings.HasPrefix(key, "home-banner/") {
+	if publicOnly && !strings.HasPrefix(key, "home-banner/") && !strings.HasPrefix(key, "avatar/") {
 		response.Error(c, http.StatusNotFound, "not_found", "文件不存在或暂不可访问")
 		return
 	}

backend/internal/modules/file/service.go

@@ -50,7 +50,7 @@ func (s *Service) Upload(req uploadRequest) (*UploadDTO, error) {
 		return nil, err
 	}
 	fileURL := "/api/files/object?key=" + url.QueryEscape(key)
-	if scene == "home-banner" {
+	if scene == "home-banner" || scene == "avatar" {
 		fileURL = "/api/public/files/object?key=" + url.QueryEscape(key)
 	}
 	return &UploadDTO{