Replace standalone catalog editor with the unified Visual Catalog studio

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.

src/app/api/admin/catalog/items/route.ts

@@ -1,5 +1,7 @@
+import { asc, eq } from "drizzle-orm";
 import { apiError, apiOk } from "@/lib/api";
 import { withAdmin } from "@/lib/api-handler";
+import { CatalogItemsBc, db } from "@/lib/db";
 import { PERMS } from "@/lib/permissions";
 import { loadCatalogItemsData } from "@/lib/services/catalog-items-loader";
 
@@ -16,6 +18,15 @@ export const GET = withAdmin(
 		if (!Number.isFinite(pageId) || pageId <= 0) {
 			return apiError("Invalid pageId");
 		}
+		const isBc = request.nextUrl.searchParams.get("catalog") === "bc";
+		if (isBc) {
+			const items = await db
+				.select()
+				.from(CatalogItemsBc)
+				.where(eq(CatalogItemsBc.pageId, pageId))
+				.orderBy(asc(CatalogItemsBc.orderNumber));
+			return apiOk({ items: jsonSafe(items) });
+		}
 		const data = await loadCatalogItemsData(pageId);
 		return apiOk(jsonSafe(data) as unknown as Record<string, unknown>);
 	},