Set up github.io site: homepage + privacy policy hosting

[Phoenix-]

Stand up a simple GitHub Pages (github.io) site for Meridian. Needed for the OAuth consent screen (homepage URL + hosted privacy policy URL) and as a general project landing page.

Why

• Google OAuth verification needs a public homepage and a publicly reachable privacy policy URL on the consent screen (see Google OAuth verification (exit test mode) #8).
• A landing page is useful regardless of verification (screenshots, download link, description).

Scope

• GitHub Pages site (likely Phoenix-.github.io/meridian or a dedicated repo).
• Host the privacy policy — canonical PRIVACY.md already exists in the repo; render it on the site.
• Homepage: app description, screenshots, scope justification, download/release link.
• (Optional/blocked) Custom domain (~$10/yr) CNAME'd to Pages — only needed if we pursue full verification, because *.github.io generally can't be verified for domain ownership in Search Console. See Google OAuth verification (exit test mode) #8 for that snag.

Notes

• Not starting now — filed so it is not forgotten. Sequence-wise this is needed before submitting verification, not before publishing to Production unverified.
• Related: Google OAuth verification (exit test mode) #8 (OAuth verification).