Document the cross-host control-plane bridge (socat TCP on tailscale0 →
colibri-daemon Unix socket): FreeBSD rc.d vs Linux systemd parity, the
interface-scoped firewall gate (pf / ufw), the "tailnet boundary is the auth"
security model (no socket auth; scope :9190 via Tailscale ACL), and config
notes (TAILSCALE_IP_REQUIRED placeholder, socket-path parity, 0770 group).
Points at packaging/{freebsd,linux}/ for install. Linked from the architecture
index next to Control Plane. No real tailnet IPs (placeholders only).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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