Function rotate_secret 

pub async fn rotate_secret(
    pool: &PgPool,
    actor: &Actor,
    id: Uuid,
) -> AppResult<(Webhook, String)>

Replaces the secret. Returns the webhook and the new secret (shown once). Deliveries that are still pending are signed with the new secret.

Invariants

• Permission: administrator (403); unknown webhook is “not found”.
• Locks: the webhook row (FOR UPDATE).
• Data: the new secret is returned once; the audit record holds only its hint.
• Audit: webhook.rotate_secret.
• Notifications / webhooks: none.
• Atomic: one transaction.