[Feature Request] Add landscape cover formats for LinkedIn, Meetup, and Facebook events

The asset generator currently only exports event covers in square (1:1 / 1000x1000) and portrait (4:5 / 1080x1350) formats. When publishing and listing events across platforms such as LinkedIn Events, Meetup, and Facebook Events, these vertical/square assets get severely cropped or don't fit the required landscape banners.

With event outreach starting in full swing, organizers need standard landscape presets to publish event listings without manual resizing.