feat(ui): add a desktop panel rail to each sidebar

Each side stack hosts a Vue rail listing its panels; selecting one opens it
through PanelChrome. The shell owns one Vue runtime and Pinia instance, and a
panel store mirrors each side's panels from the DOM. The rail hides with its
stack, in Cockpit, clean view and recording, and on phones. Panels without a
catalog entry get a generic item, and Data Layers leaves the rail while the
f shortcut hides it.

src/i18n/locales/zh-CN.json

@@ -2873,5 +2873,7 @@
   "Play from this scene through the rest of the project": "从此场景开始播放项目中的其余场景",
   "Play the shot after the selected one, moving on to the next scene when needed": "播放所选镜头的下一个镜头，必要时进入下一个场景",
   "Edit anchors, data packs and shot details": "编辑锚点、数据包和镜头详情",
-  "Download this scene as JSON or an asset bundle": "将此场景下载为 JSON 或资源包"
+  "Download this scene as JSON or an asset bundle": "将此场景下载为 JSON 或资源包",
+  "Left panels": "左侧面板",
+  "Right panels": "右侧面板"
 }