Send a transactional email

Requires a non-empty mailing address in the team's general settings. `templateId` must identify a team-owned transactional template; marketing templates return 422 template_not_transactional. Unguarded Liquid variables must be supplied in `variables`, or the API returns 422 missing_template_variables without creating a row or queue job. Inline `html` is sent verbatim without Liquid rendering. address, unsubscribe_link, and subscriber are marketing-only server-owned values and are unavailable to transactional templates.

curl -X POST "https://api.sendlit.dev/emails" \  -H "Content-Type: application/json" \  -d '{    "to": "user@example.com",    "subject": "string"  }'

{
  "txeId": "string",
  "status": "queued"
}

{
  "error": "string"
}

{
  "error": "missing_template_variables",
  "missingVariables": [
    "string"
  ]
}

{
  "error": "string"
}