[sneridagh]

Aligns the @blocks-schema endpoint (#299) with the document model changes in Volto, plone/volto#8503.

Aurora stores a page as one Plate document in blocks.__somersault__, which is the plone.plate document model.

Changes

• @plone/plate docs: every element docs file has document_model: plone.plate. document.block.md has only document_model: plone.plate, no block: __somersault__. Block docs are unchanged: a block's data is the same in every model.
• @plone/registry loader (ported from Announce the document model in the @blocks-schema endpoint volto#8503):
  • Element sources carry document_model, keyed element:${document_model}:${name}, so two models can each have an element with the same name.
  • A file with only document_model is the docs of that model: { document_model, path }.
  • The warning names block, element and document_model.
  • virtual/blocks-docs.d.ts lists document_model.
• @plone/cmsui endpoint:
  • The list returns document_model: { id: 'plone.plate', version: 1 } before document.
  • document comes from the plone.plate model docs, not from the __somersault__ block lookup.
  • Only elements of plone.plate are listed. The plateBlocksConfig filter is unchanged.
  • The Markdown list has _Document model \plone.plate`, version 1._under## Document format`, as in Volto.
  • ?type=<type>: with a content path, it replaces the contentType that restricted receives. The list @id and the item links keep ?type=. Aurora has one model, so type doesn't change it, and document_models is never returned.
• Docs: the endpoint reference and the "Document your blocks" guide cover document_model, the frontmatter, and ?type=.

Announcing the model from the backend, through an FTI setting in @content-types (plone/plone.restapi#2070), is a later step tracked in plone/volto#8502. This PR makes no backend calls.

Testing

• pnpm --filter @plone/registry test, pnpm --filter @plone/plate test, pnpm --filter @plone/cmsui test: all pass.
• check:ts passes for registry, plate and cmsui. ESLint passes on the changed files.
• packages/cmsui/acceptance/tests/blocks-schema.test.ts is updated, with a new test for ?type=. I didn't run it locally; CI runs it.