i18n(plugins): relabel "group by type" as "group by format"

The installed-extensions grouping is by extension format (plugin / MCP / skill),
so rename the toggle label accordingly across all 8 locales (key unchanged).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/src/i18n/locales/zh-Hans.ts

@@ -438,7 +438,7 @@ const zhHans = {
     noPluginInstalled: '暂未安装任何插件',
     noExtensionInstalled: '暂未安装任何扩展',
     loadingExtensions: '正在加载扩展...',
-    groupByType: '按类型分组',
+    groupByType: '按格式分组',
     pluginSort: '插件排序',
     pluginSortDescription:
       '插件顺序会影响同一事件内的处理顺序，请拖动插件卡片排序',