fix(docs): drop the archived VS Code extension content source

[jimisola]

ⓘ The Pages build has been failing since 2026-05-27. This unblocks it.

What & Why

The playbook pulled docs from reqstool-vscode-extension, which is archived and private — so Antora cannot fetch it:

FATAL (antora): Content repository not found or requires credentials
(url: https://github.com/reqstool/reqstool-vscode-extension)

That repo is superseded by reqstool-vscode and is no longer used, so the source is removed rather than repointed — reqstool-vscode carries no docs module to point at (verified: it has no docs/ directory).

Removed from both docs/antora-playbook.yml and docs/local-antora-playbook.yml.

The part that is easy to miss

Three pages cross-referenced the removed module:

Page
getting-started.adoc:32	xref:reqstool-vscode-extension::index.adoc
index.adoc:62	same
components.adoc:81	same

Dropping the source alone would leave these rendering as broken links — Antora treats an unresolved xref as a warning, and the build passes --log-failure-level=fatal, so it would have gone green while quietly shipping three dead links. They now link to the repository directly.

Follow-up

When reqstool-vscode grows a docs module, these can go back to being xrefs and the content source can be added again. Worth noting the extension was rewritten, so the archived docs described the old implementation — recovering them verbatim is probably not wanted anyway.

Author checklist

• Both playbooks updated
• No dangling vscode-extension references remain anywhere under docs/
• Conventional Commit title, DCO sign-off

Test Plan

CI on this PR builds the site. After merge, Publish to GitHub Pages on main should go green for the first time since May.