Add van-br0-setup.service to fix bridge member persistence on boot

systemd-networkd Bridge= directive wasn't reliably adding interfaces to br0
on Armbian. Created persistent systemd service to ensure enP2p33s0 and wlp1s0
are added to the bridge after boot, maintaining 10.42.1.0/24 network.

This ensures the gateway bridge stays configured even after R5C reboots.
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

ap/van-br0-setup.service

@@ -0,0 +1,13 @@
+[Unit]
+Description=VanLink bridge member setup
+After=systemd-networkd.service hostapd.service
+Wants=systemd-networkd.service hostapd.service
+
+[Service]
+Type=oneshot
+ExecStart=/bin/bash -c "brctl addif br0 enP2p33s0 2>/dev/null || true"
+ExecStart=/bin/bash -c "brctl addif br0 wlp1s0 2>/dev/null || true"
+RemainAfterExit=yes
+
+[Install]
+WantedBy=multi-user.target