Add `ProfilePage` microdata to enhance SEO and AI capabilities

[czerkies]

• https://html.spec.whatwg.org/multipage/microdata.html
• https://schema.org/ProfilePage
• https://schema.org/mainEntity
• https://schema.org/Person
• https://developers.google.com/search/docs/appearance/structured-data/profile-page
• https://developer.apple.com/documentation/sirieventsuggestionsmarkup/person