Canonical host williamlay.co.uk (apex): CNAME + DNS

Canonical host is the apex, https://williamlay.co.uk, for v2 as for v1. Decided 2026-09-15: v1 is already indexed on the apex, the Search Console Domain property is verified, and switching to www would cost a re-indexing transition for no concrete gain. This matches docs/overhaul/architecture.md and astro.config.mjs (site: "https://williamlay.co.uk") on main.

• public/CNAME = williamlay.co.uk (added at cutover)
• DNS: apex A/AAAA → GitHub Pages; www CNAME → laywill.github.io so GitHub serves the www → apex redirect.

Acceptance criteria

• Apex resolves to GitHub Pages (4× A, 4× AAAA in place, verified 2026-09-15)
• www CNAME → laywill.github.io; http://, https://www. and laywill.github.io all 301 to https://williamlay.co.uk/ with valid HTTPS (verified 2026-09-15 against v1)
• public/CNAME on main = williamlay.co.uk
• All canonical URLs, sitemap entries and OG tags on main use the apex host
• Stale www references on main fixed: README.md ("Canonical host") and docs/overhaul/content-audit.md (CNAME line)

Start by inspecting public/CNAME on main, then search the repository for www references and review README.md, docs/overhaul/content-audit.md, astro.config.mjs, sitemap entries, and OG tags. Confirm the apex host is used consistently and verify the listed redirects and HTTPS behavior; done means every acceptance criterion is checked on main.