🤖 Invite links now show a proper preview card when you paste them into Messages,
WhatsApp, Slack and the like. The card reads "You're invited to <your group's
name>" and shows your server's photo — or the app logo if you haven't set one —
instead of a bare link. Nothing private leaks: the preview only uses your group's
name and photo (both already public branding), never anyone's screen name, which
stays end-to-end encrypted as always.