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/it.json

@@ -3013,5 +3013,7 @@
   "Load scenes from an exported JSON file": "Carica le scene da un file JSON esportato",
   "Download the timing log of the last play": "Scarica il log dei tempi dell'ultima riproduzione",
   "Edit anchors, data packs and shot details": "Modifica ancore, pacchetti dati e dettagli degli scatti",
-  "Download this scene as JSON or an asset bundle": "Scarica questa scena come JSON o pacchetto di risorse"
+  "Download this scene as JSON or an asset bundle": "Scarica questa scena come JSON o pacchetto di risorse",
+  "Left panels": "Pannelli a sinistra",
+  "Right panels": "Pannelli a destra"
 }