feat(studio): localize catalog studio UI and polish responsive layout

Route all Catalog Studio strings through the admin.studio namespace
(workspace, filters, review, inspector, quality, sync, scale32, organize
imports and page titles/subtitles) with English fallback, and add shared
StudioPage chrome plus a loading skeleton. Tighten mobile padding on the
header and sub-bars.

src/components/admin/studio/README.md

@@ -2,6 +2,10 @@
 
 `studio-client.tsx` composes the workspace, selection and actions. Keep reusable data handling outside its render tree.
 
+## Shared chrome
+
+- `studio-page.tsx`: consistent header (icon tile, title, subtitle, actions) and padding for every studio sub-page; wraps `AdminPageShell`.
+
 ## Client responsibilities
 
 - `studio-filters.ts`: pure filtering and sorting of the loaded furniture list; never mutates the input array.