Slack approval notifications

Approval notifications are beta. Configure them on the gateway and admin:

Setting	Value
notifications.enabled	true
notifications.slack_bot_token_ref and notifications.slack_channel	a bot token as a secret reference, and the channel to post to (preferred)
notifications.slack_webhook_url_ref	or an incoming-webhook URL, as a secret reference
notifications.admin_base_url	the console’s URL, so messages link to the approval
notifications.approval_events	which of pending, approved, rejected, expired, failed to send

As environment variables these are INTERLOCK_NOTIFICATIONS__ENABLED and so on. The bot needs chat:write and must be in the channel.

Each message names the approval, the source, the identity and the risk, with the statement’s literals replaced, and a link to its page. Delivery happens in the background with bounded retries: a Slack outage never delays or fails an agent’s request, but a message can be lost if the gateway stops between queueing and sending. The approval itself is always in Write Safety.