chore(release): 0.15.2

- bump version: package.json / dsh.plugin.json / SIDEBAR_SERVICE_VERSION
- README / README_EN: feature tour converted to a table (two screenshots
  per row, saves space); add v0.15.2 changelog (file-tree open-in-app
  menu #334, tab context menu #331, diff collapse by default #270, prune
  empty restored panes #268, hide git windows on Windows #301, untracked
  files inside new folders #242, toggle/drag per-frame re-render perf
  #315); community QR codes landed in #325

dsh.plugin.json

@@ -1,6 +1,6 @@
 {
   "id": "dsh-external/dsh-better-sidebar",
-  "version": "0.15.1",
+  "version": "0.15.2",
   "main": "./lib/index.js",
   "description": "VSCode 风格右侧侧边栏：文件资源管理器 / 编辑器 / 终端 / Git / 浏览器，按会话隔离。暴露服务供其他插件注册侧边栏页面和文件预览器",
   "engines": {