Add ScrobbleEmbedPage and getScrobble xrpc, and register a new /embed/:did/scrobble/:rkey route to render scrobbles with profile data. Update Scrobble type (cover?, date) and change song/artist/album routes to use :did/:rkey params. Add various Tailwind utility classes and tweak the embed index layout to include a centered input. Add placeholder xrpc stubs for album/artist/song.