feat(search): Bring Search Everywhere closer to IDEA's popup

- All tab interleaves classes, files, symbols, actions and text by match
  degree, keeping each source's own order; Enter waits for every source
  except a text search the top row already beats.
- Preview pane under the list (remembered toggle), reusing CodePreview.
- "/" lists scope commands; "/files q" switches scope and searches q.
- Per-tab search history: magnifier dropdown and ⌥↑ / ⌥↓.
- Text hits: syntax colouring, IDEA's boxed-T icon, dimmed repeated file
  names, collapsed indentation.
- Flat scope chooser, IDEA header icons, wider popup with a stable list
  height; the list shrinks so the footer stays visible.

src/platform/locales/text/zh.json

@@ -1161,6 +1161,7 @@
   "No Maven projects": "没有 Maven 项目",
   "No profile for '{name}'": "没有 '{name}' 的分析数据",
   "No Python found": "未找到 Python",
+  "No recent searches": "无最近搜索",
   "No TODO items found": "未找到 TODO 项",
   "No TODO items in this file": "此文件中没有 TODO 项",
   "No active editor": "没有活动编辑器",
@@ -1494,6 +1495,7 @@
   "Recent files": "最近的文件",
   "Recent locations": "最近的位置",
   "Recent projects": "最近的项目",
+  "Recent Searches": "最近搜索",
   "Recently Viewed Files": "最近查看的文件",
   "Record": "记录",
   "Red": "红色",
@@ -1707,6 +1709,8 @@
   "Runs the language server's Organize Imports action.": "运行语言服务器的“整理导入”操作。",
   "Runs the language server's formatter before an explicit save (Actions on Save).": "在显式保存前运行语言服务器的格式化程序（保存时操作）。",
   "Runs this project": "运行此项目",
+  "Search history": "搜索历史",
+  "Search history (⌥↑ / ⌥↓)": "搜索历史（⌥↑ / ⌥↓）",
   "Searching for usages of '{symbol}'": "正在搜索 '{symbol}' 的用法",
   "SQL Inserts": "SQL Insert 语句",
   "SQL Script Template": "SQL 脚本模板",
@@ -2108,8 +2112,8 @@
   "Trust and Connect": "信任并连接",
   "Tx: Auto": "事务：自动",
   "Tx: Manual": "事务：手动",
+  "Type / to see commands": "输入 / 查看命令",
   "Type Declaration": "类型声明",
-  "Type file name, path or file:42": "输入文件名、路径或 file:42",
   "Type Hierarchy": "类型层次结构",
   "Type an expression followed by": "输入表达式，后跟",
   "Type hierarchy": "类型层次结构",
@@ -2341,7 +2345,6 @@
   "· read-only": "· 只读",
   "… more": "… 更多",
   "↵ Open · ⇧↵ Open to the side · ⌘↵ Open in Find Window": "↵ 打开 · ⇧↵ 在侧边打开 · ⌘↵ 在查找窗口中打开",
-  "⇥ to switch scope": "⇥ 切换范围",
   "⌘↵ to open in Find tool window": "⌘↵ 在“查找”工具窗口中打开",
   "⌥← / ⌥→ and ⌥⌫ stop at humps of camelCase names.": "⌥← / ⌥→ 和 ⌥⌫ 会在 camelCase 名称的驼峰处停止。",
   "Specify commit message": "请填写提交信息",