/**
 * Only Slack renders `<url|label>`, so it is the one format that gets labeled
 * links. iMessage / owner-scoped rush / command / desktop sinks stay `plain`
 * (they can't turn `claude/6fc1db18` blue, and dumping the raw URL is worse than
 * leaving the crumb unlinked — PHNX-3698).
 *
 * The argument is the **resolved provider name**, not a sink's declared channel:
 * an operator can point an arbitrary channel name at the Slack provider through
 * `notify.transports` (e.g. `eng-alerts -> slack`), and delivery keys off that
 * resolved provider (`lookupTransport`), so the format decision must too —
 * otherwise an aliased Slack sink would compose plain while delivering to Slack,
 * or a name remapped AWAY from Slack would emit `<url|label>` markup a non-Slack
 * transport shows literally.
 */
export function sinkMessageFormat(provider) {
    return provider?.trim().toLowerCase() === 'slack' ? 'mrkdwn' : 'plain';
}
