Make /admin/catalog a full-screen catalog studio that replaces the old
listing plus separate [id]/builder-club detail pages:
- Embed CatalogManagerWorkspace on /admin/catalog with a Normal/Builder
Club toggle, Catalog Sync status, packages (normal), Organize imports
and a diagnostics link to /admin/studio/maintenance.
- Manage BC items directly in the studio Items tab (new BcItemsEditor,
CRUD via existing bc actions; /api/admin/catalog/items now serves BC).
- Inline editor: add pageTextTeaser field for both catalogs and remove
the legacy full-editor links.
- Remove the 'Open full editor' context action from the tree.
- Move catalog-items-table (dir + barrel) and catalog-translate-tab out
of the app route into src/components/admin/catalog and update all
importers.
- Keep /admin/catalog/[id], builder-club/[id] and /admin/catalog/maintenance
as redirects into the new studio; consolidate maintenance panels into
/admin/studio/maintenance and point the nav item there.
- Delete the old listing/table/tabs/forms and the standalone bc-manager.
