docs: README (Node 22, v4, skills.sh) e retorno de list na skill

[andrenfe]

Ajustes só de documentação no repo, sem mudança de versão:

• README: Node 18 → 22 (Recursos + Requisitos); rótulos v3 → v4; badge + seção Skill para Agentes de IA com npx skills add nfe/client-nodejs.
• skills/nfeio-node-sdk/SKILL.md: corrige o shape de retorno de list, que era impreciso — serviceInvoices.list retorna { serviceInvoices, totalResults, totalPages, page } (não data/totalCount); companies/people/webhooks usam o genérico ListResponse<T> ({ data, totalCount?, page }); productInvoices usa { productInvoices, hasMore }.

[github-actions]

📋 OpenAPI Spec Validation

✅ All specs validated and types generated successfully

Specs processed:

• calculo-impostos-v1.yaml - 27.90 KB, 853 lines
• consulta-cnpj.yaml - 34.28 KB, 1128 lines
• consulta-cpf.yaml - 3.39 KB, 83 lines
• consulta-cte-v2.yaml - 18.33 KB, 578 lines
• consulta-endereco.yaml - 11.17 KB, 343 lines
• consulta-nf-consumidor.yaml - 43.41 KB, 1279 lines
• consulta-nf.yaml - 137.87 KB, 3119 lines
• consulta-nfe-distribuicao-v1.yaml - 53.07 KB, 1775 lines
• nf-consumidor-v2.yaml - 293.87 KB, 7609 lines
• nf-produto-v2.yaml - 309.41 KB, 8204 lines
• nf-servico-v1.yaml - 257.42 KB, 6252 lines
• nfeio.yaml - 15.86 KB, 630 lines

Generated types available as artifact in src/generated/.