Error responses

Errors on /api/v1/* share one body shape, with the meaning carried by the HTTP status code:

{
	"message": "Bad Request",
	"errors": [
		{
			"field": "name",
			"message": "The name field is required"
		}
	]
}

Clients should branch on the status, not on message:

Status	Meaning
400	Malformed request that carries no more specific status
401	Token missing, expired or revoked — reconnect rather than retry
403	Authenticated, but the resource belongs to someone else
404	No such collection or link
422	Validation failed; errors lists the offending fields
429	Rate limit exceeded — see Rate limiting
500	Unexpected server error