`[2026-09-22]` irv-ml1: Irvine is a TENANCY behind a Fortinet PFI does not control

irv-ml1: Irvine is a TENANCY behind a Fortinet PFI does not control — its TLS inspection breaks Tailscale relay/control intermittently (41 cert warnings/week). No fix on our side; do not go looking. ⚠ Diagnose reachability with tailscale ping, NOT status output — headscale said online and status said active, 19.7GB while nothing answered. Commit 38bb20c.