- Add og:title, og:description, og:image, og:type, og:site_name and
twitter:card meta tags to base template with Askama block overrides
- Create static 1200x630 OG image served at /og-image.png
- Override OG blocks with entity-specific content on brew, cup, and
stats detail pages
- Reuse BREWLOG_RP_ORIGIN as base URL for absolute og:image URLs via
OnceLock initialized at server startup
