Refine GitHub Pages presentation layout

[xtraid]

Summary

• introduce explicit reading, presentation, and shell widths without widening technical prose
• add data-driven homepage components for pipeline, verified output, evidence, and status; they remain absent until author-approved data is supplied
• refine document H1, navigation responsiveness, contrast, homepage semantics, and catalog composition while preserving the existing visual identity
• validate generated Pages output and internal links in CI

Verification

• make pages-check
• PYTHONDONTWRITEBYTECODE=1 python3 -m unittest discover -s tests/python -p "test_generated_pages.py" -v (3/3)
• official GitHub Pages/Jekyll build (22 pages)
• generated-site audit (22 pages, 341 references)
• JavaScript syntax checks
• git diff --check

Intentionally deferred

• author-written narrative copy and final scientific diagram topology
• selection/caption of the real verified output artifact
• final navigation destinations and wording
• optional sticky desktop TOC
• publication/deploy decision

The Wang-field JavaScript and hero concept are unchanged. Browser-based responsive review is being completed separately and any finding will be pushed to this PR.