FE-1757: Move HASH embed chrome onto the plugin API and remove slots

[kube]

Summary

Before this PR, HASH's process embed passed its breadcrumbs, title style, version picker and Save button to the editor through the slots prop, the last host to use it.

This PR moves that chrome into a HASH plugin with two top-bar items and removes slots from @hashintel/petrinaut: its prop, its type, its exports and its rendering in the top bar and the Labs settings.

Links

• Docs Host integration

Changes

Library

• slots prop and PetrinautSlots type removed

  Top-bar items and Labs rows come from plugins.

HASH

• embedChromePlugin places the breadcrumbs at the start of the top bar and the version picker and Save at its end

  The page provides its state to both items through EmbedChromeContext.

Known issues

• The chrome plugin can be switched off under Plugins, which hides Save for the session

Test coverage

• user-settings.test.tsx:

  Labs settings without host content.

• @apps/hash-frontend type check and lint.

How to test

• Open HASH preview on Vercel
• Processes > any process

  Expect breadcrumbs with the editable title at the start of the top bar

• Edit the net

  Expect Save enabled at the end of the top bar

[vercel]

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Project	Deployment	Actions	Updated
hash	Ready	Preview	Oct 9, 2026 2:54am UTC
petrinaut	Ready	Preview	Oct 9, 2026 2:54am UTC
petrinaut-docs	Ready	Preview	Oct 9, 2026 2:54am UTC

1 Skipped Deployment

Project	Deployment	Actions	Updated
hashdotdesign-tokens	Ignored	Preview	Oct 9, 2026 2:54am UTC

[CLAassistant]

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