Update and expand ai-assisted service runbooks

The runbooks related to the ai-assisted service’s Apdex score fluctuations are sparse and have broken links. Updating and expanding these runbooks could provide clearer, actionable steps for future incidents. The service catalog is also incomplete with several fields missing including the owners https://gitlab.com/gitlab-com/runbooks/-/blob/master/services/service-catalog.yml?ref_type=heads#L2407.

This ticket was created from INC-2718 and was automatically exported by incident.io 🔥