Adds a public (0.0.0.0/0) zone and askari's Caddy (80/443) + NetBird STUN
(3478/udp) ingress so the base nftables default-deny does not drop the live
public services when applied to askari. Molecule + filter unit test cover the
public-zone rendering. Mesh-hardening 1/3 (ADR-020/024/016).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>