ci: use Node 24 Pages actions

[Pluze]

Why

The first source-built Pages deployment passed but reported that the configured official Pages Actions still targeted deprecated Node.js 20 and were being forced onto Node.js 24 by the runner. GitHub has published supported Node.js 24 major releases for all three affected Actions.

What changed

• Upgraded actions/configure-pages from v5 to v6.
• Upgraded actions/upload-pages-artifact from v4 to v5.
• Upgraded actions/deploy-pages from v4 to v5.
• Extended the repository architecture test to pin all three supported major versions.

Evidence

matlab -batch "buildtool changedFast"
56 tests, 0 failed, 0 incomplete

Ruby YAML parse
docs-pages.yml parsed successfully

First source-built deployment
Passed in 2m 7s; warning identified the three deprecated Node.js 20 Action majors

Risks and follow-up

This changes only official GitHub Pages Action major versions; documentation inputs, generated files, launcher behavior, MATLAB behavior, and scientific results are unchanged. The PR validates repository policy and MATLAB coverage, and its merged-main Pages run must confirm a warning-free deployment.

Author confirmation

• The final diff matches the stated scope and contains no unrelated change.
• The evidence above covers required local and manual validation; every
  remaining unverified boundary is explicit.
• The diff contains only synthetic or generic public data, with no private
  App details, lab identifiers, local paths, or recognizable sample values.