Card lifecycle and public pages

Cards now move through three states: staged, published, and revoked. A creator downloads a staged card, publishes it with a content title and platform link, and can revoke it later with a reason. Publishing ends on a share screen, and every card has its own public page. I added a demo status page, an overlay page for OBS, a QR overlay page, and pricing on the landing page, and redesigned the status page, the single card view, and the profile header.