feat(api): add GET /redirects/{domain}/check endpoint

[igoramf]

Summary

Novo endpoint GET /redirects/{domain}/check para o botão "Validate" do admin.

Retorna o status de emissão do certificado:

Status	Significado
ready	Certificado emitido ✅
issuing	Sendo gerado, aguardar alguns minutos
dns_issue	Emissão falhou — usuário deve verificar registros DNS

Motivação

Hoje o validate retorna "Certificate is not ready yet" em qualquer falha, sem contexto. Este endpoint permite ao admin mostrar feedback específico e acionável ao usuário.

Uso

GET /redirects/client.com/check

# cert pronto
{"status":"ready"}

# sendo gerado
{"status":"issuing","message":"Certificate is being generated, please wait a few minutes."}

# DNS errado
{"status":"dns_issue","message":"Certificate issuance failed. Please check your DNS records..."}

🤖 Generated with Claude Code

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Summary by cubic

Adds a new GET /redirects/{domain}/check endpoint that returns the certificate issuance status for a domain. This powers the admin “Validate” button with clear, actionable feedback.

• New Features
  • Added GET /redirects/{domain}/check returning JSON: status = ready | issuing | dns_issue (with optional message).
  • Validates domain and ensures the redirect exists; returns 404 if not found.
  • Determines status from cert-manager Certificate conditions: Ready=true → ready; Issuing=false with reason "Failed" → dns_issue; otherwise → issuing.

^{Written for commit 249b32f. Summary will update on new commits.}