One A2A agent: its card's skills and capabilities, protocol, health and the registries that list it.

The same row as the list plus what the card declares: every skill, the capabilities object, the protocol version as written, the documentation and icon URLs, and when we first saw it. Cached for 60 seconds; a MAT catalog read, like the list. Returns: { ok, agent{chave,dominio,nome,descricao,url,cartao,publicador,protocolo,saudavel,conforme,verificado,uptime,skills_n,tags,fontes,creditos,visto_em,protocolo_declarado,documentacao,icone,capacidades,skills,primeiro_em} }