setup-ovn.sh's veth branch creates veth-wan-br ↔ veth-wan-ovs but nothing
recreates the kernel interfaces on reboot. OVSDB remembers veth-wan-ovs
as a port on br-ext but the peer is gone — the external path silently
breaks and vpcd falls through to direct mode.
- setup-ovn.sh: write /etc/systemd/network/15-spinifex-veth-wan.{netdev,network}
in the veth branch so systemd-networkd recreates the pair on boot. Add
a single pre-case guard that rips down stale veth persistence + the OVS
port + the kernel veth whenever WAN_BRIDGE_MODE != veth, so mode
transitions are idempotent (D17).
- reset-dev-env.sh: delete the netdev/network units during cleanup so
`make reset` gives a truly clean slate.
- spinifex-vpcd.service: After=systemd-networkd.service openvswitch-switch.service
so vpcd's sanity checks see a populated kernel + OVSDB (D5).
joshsiv-mulga