feat(web): add stepwise session preview controls (#1266)

* feat(web): add stepwise session preview controls

* fix(web): avoid no-op session preview collapse

* fix(web): expand previews from rendered count

web/src/lib/locales/zh-CN.ts

@@ -71,8 +71,8 @@ export default {
   'sessions.timeFilter.previousMonth': '上个月',
   'sessions.timeFilter.nextMonth': '下个月',
   'sessions.timeFilter.dayWithActivity': '{date}，有会话活动',
-  'sessions.group.showMore': '再显示 {n} 个',
-  'sessions.group.showLess': '收起',
+  'sessions.group.expand': '展开 {n} 个',
+  'sessions.group.collapse': '收起 {n} 个',
   'sessions.group.new': '在此目录新建会话',
   'sessions.machineFilter.label': '按机器筛选会话',
   'sessions.machineFilter.all': '全部',