Fix dnsmasq startup dependency: require bridge setup before DHCP

dnsmasq was failing to start or staying inactive because it was starting
before the bridge members were added. Updated van-ap-dnsmasq.service to
depend on van-br0-setup.service, ensuring the bridge is ready before
dnsmasq binds to br0.

Fixes: DHCP not provisioning addresses on boot.
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

ap/van-ap-dnsmasq.service

@@ -1,7 +1,7 @@
 [Unit]
 Description=dnsmasq DHCP+DNS for van-ap AP
-After=hostapd.service
-Wants=hostapd.service
+After=hostapd.service van-br0-setup.service
+Wants=hostapd.service van-br0-setup.service
 [Service]
 ExecStartPre=/usr/sbin/dnsmasq --test --conf-file=/etc/van-ap/dnsmasq.conf
 ExecStart=/usr/sbin/dnsmasq --keep-in-foreground --conf-file=/etc/van-ap/dnsmasq.conf