fix: 修复社交账号绑定 Extra 字段 JSON 空值报错

apis/daytask/user.go

@@ -322,6 +322,7 @@ func (s *Server) SocialBind(c *gin.Context) {
 			Platform: req.Platform,
 			Account:  req.Account,
 			Nickname: req.Nickname,
+			Extra:    "{}",
 			Status:   1,
 		}
 		db.Create(social)