List Channels
config (PagerDuty routing keys, Slack webhook URLs, webhook secrets) are masked in the response.
Create a Channel
channel_type must be pagerduty, slack, webhook, or email. Any webhook URL in config is validated at creation time to guard against SSRF.
Update a Channel
channel_type cannot be changed after creation. Any of name, config, enabled, events may be updated.
Delete a Channel
204 No Content on success.
Send a Test Notification
200 OK with success: false and a message explaining the failure, rather than an HTTP error.
