fix(custom-widgets): harden v2 authoring

apps/docs/package.json

@@ -18,6 +18,7 @@
     "write-translations": "docusaurus write-translations",
     "write-heading-ids": "docusaurus write-heading-ids",
     "api-dump-contributors": "node ./scripts/dump-contributors.mjs",
+    "check:custom-widgets-ste": "node ./scripts/check-custom-widgets-ste.mjs",
     "verify:search": "node ./scripts/verify-algolia-search.mjs"
   },
   "dependencies": {