feat(seo): og:image light/dark override setting
The auto-generated share card followed the site's default theme (1.2.0); Admin →
SEO now has an explicit override: Auto (follow site theme) / Light / Dark.
- src/config/database.js — sites.og_theme column (NULL = auto).
- src/services/OgImageService.js — og_theme wins over theme_override when set.
- src/routes/og.js — select og_theme for the card route.
- src/routes/admin-seo.js — save og_theme (validated to light/dark, else auto).
- src/views/pages/admin-seo.ejs — select under the share-image field.
- src/services/i18n.js — aseo.og_theme* (nl/en/de).
- CHANGELOG(.nl/.de).md — under Added.
Closes prutfolio-src-krm.
Co-Authored-By: Claude <noreply@…>