Admin: dedicated SEO page (/admin/seo) for advanced SEO
The <head> already consumed a rich SEO set (title_template, canonical,
default_description, og_image_default, og_locale, author, *_verification,
facebook_app_id, publisher_*/schema_type for JSON-LD), but many fields
had nowhere to be edited. New god-only page manages the full set for the
primary site, accessible via a 🔎 SEO button in /admin.
The old hidden SEO block in Appearance has been removed (+ its columns
from the appearance-save so saving no longer zeroes them out) and replaced
with a link to the new page — single source of truth.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@…>