doc: imitate unordered bundle to recover tocs

[Becheler]

The current documentation pipeline has two problems:

1. Left ToC is not collapsible
2. Right ToC (for intra-page documentation) does not show properly

Before submitting

• This PR targets the develop branch.
• I searched for an existing PR or issue covering the same change.
• My contribution is licensed under the Boost Software License 1.0.

Type of change

• Bug fix
• New feature or API addition
• Refactor (no behavior change)
• Documentation
• Build, CI, or tooling
• Other (specify below)

Does this PR introduce a breaking change?

• Yes (describe migration impact below)
• No

What this PR does

• doc/playbook.yml ui: block repointed to the Unordered bundle; supplemental_files and the playbook page-toc removed.
• doc/antora.yml added page-toc: ' ' under asciidoc.attributes.
• doc/supplemental-ui/ deleted.

Motivation

Graph's docs put their collapsible-nav fix in a supplemental_files overlay and the right-rail page-toc attribute in the playbook, but Antora only ships UI partials from the site-level ui.bundle and neither overlays nor playbook attributes travel with the component, so any deploy not running Graph's own playbook dropped both (no folding left ToC, no right nav). The fix was to imitate Boost.Unordered: point the playbook at a self-hosted bundle that bakes those behaviors in (unordered-ui-bundle), delete the overlay, and move page-toc into antora.yml where it travels with the component.

Testing

Can't test without merging on develop.

Checklist

• Existing tests pass (b2 in the test/ directory).
• New behavior is covered by a test, or this is a docs / build / refactor change.
• Documentation was updated if user-facing behavior changed.
• No new compiler warnings on the platforms I built against.

[cppalliance-bot]

An automated preview of the documentation is available at https://519.graph.prtest3.cppalliance.org/index.html

If more commits are pushed to the pull request, the docs will rebuild at the same URL.

2026-07-01 08:05:36 UTC