feat(frontend): add JSON script import functionality (#11563)

Allow users to import scripts into the JSON editor via local file
upload or by selecting from the existing script library.

- Dropdown toggle for 'Local' and 'Library' import sources.
- Script selection dialog with category and search filters.
- Global search using the existing command menu logic.

frontend/src/components/command-menu.tsx

@@ -23,7 +23,7 @@ import { Button } from "./ui/button";
 import { Badge } from "./ui/badge";
 import Link from "next/link";
 
-function search(scripts: Script[], query: string): Script[] {
+export function search(scripts: Script[], query: string): Script[] {
   const queryLower = query.toLowerCase().trim();
   const searchWords = queryLower.split(/\s+/).filter(Boolean);