Create format template

curl --request POST \
  --url https://api.case.dev/format/v1/templates \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "name": "<string>",
  "type": "caption",
  "content": "<string>",
  "description": "<string>",
  "styles": {},
  "variables": [
    "<string>"
  ],
  "tags": [
    "<string>"
  ]
}
'

{
  "id": "tmpl_abc123",
  "name": "Legal Brief Caption",
  "type": "caption",
  "variables": [
    "caseNumber",
    "court",
    "plaintiff",
    "defendant"
  ],
  "createdAt": "2024-01-15T10:30:00Z"
}