28 alert rules across 9 PrometheusRule files covering infrastructure (Longhorn, cert-manager), data (PostgreSQL, OpenBao, OpenSearch), storage (SeaweedFS), devtools (Gitea), identity (Hydra, Kratos), media (LiveKit), and mesh (Linkerd golden signals for all services). Severity routing: critical alerts fire to Matrix + email, warnings to Matrix only (AlertManager config updated in separate commit).