rego-tunnel: use VM_NET_IP env var directly instead of detecting

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/rego-tunnel/vpn_scripts/start.sh

@@ -15,16 +15,12 @@ cp /vpn_scripts/id_ed25519-lenovo /root/.ssh/ 2>/dev/null || true
 chmod 600 /root/.ssh/id_ed25519-lenovo 2>/dev/null || true
 
 get_windows_ip() {
-  # Method 1: DHCP leases (hostname is "Windows")
-  local ip=$(awk '/Windows/ {print $3}' /var/lib/misc/dnsmasq.leases 2>/dev/null | head -1)
-  if [[ -n "$ip" ]]; then echo "$ip"; return; fi
-
-  # Method 2: ip neigh (ARP table) - look for 172.32.x.x on docker interface (VM_NET_IP subnet)
-  ip=$(ip neigh show dev docker 2>/dev/null | grep -oE '172\.32\.[0-9]+\.[0-9]+' | head -1)
-  if [[ -n "$ip" ]]; then echo "$ip"; return; fi
-
-  # Method 3: qemu.ip file (if available)
-  cat /run/shm/qemu.ip 2>/dev/null || true
+  # Use VM_NET_IP env var if set, otherwise detect from DHCP leases
+  if [[ -n "${VM_NET_IP:-}" ]]; then
+    echo "$VM_NET_IP"
+    return
+  fi
+  awk '/Windows/ {print $3}' /var/lib/misc/dnsmasq.leases 2>/dev/null | head -1
 }
 
 get_container_ip() {