Messages-format OG card is now the primary unfurl on every page
Chat-preview is the surface most readers will see the splash through first — iMessage, WhatsApp, Slack, Discord all crop unfurls to a square-ish landscape, and the old 1.78:1 banner crop weirdly. The new 890×760 Messages card (real JPEG, no ImageKit content-negotiation surprise) fits that crop natively and is now what every page emits in its og:image sextet.