feat(rego-tunnel): Add Dockerfile and build scripts for cisco-vpn image

Includes:
- Dockerfile for native Cisco Secure Client in Docker
- Build scripts (init-vpn.sh, startup-vnc.sh, vpn-connect.sh)
- VNC configuration (xstartup, vnc.service)
- build.sh for manual image builds
- README documenting the architecture

Note: cisco-secure-client-full.tar.gz is gitignored (large binary)
Copy it from ~/projects/cisco-vpn/build/ before building.

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

apps/rego-tunnel/build/scripts/startup-vnc.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+# VNC and noVNC startup script
+
+set -e
+
+export HOME=/root
+export USER=root
+
+# Clean up any existing VNC locks
+rm -f /tmp/.X1-lock /tmp/.X11-unix/X1 2>/dev/null || true
+rm -rf /tmp/.X*-lock /tmp/.X11-unix/* 2>/dev/null || true
+
+echo "Starting TigerVNC server on display :1..."
+vncserver :1 \
+    -geometry 1280x800 \
+    -depth 24 \
+    -SecurityTypes VncAuth \
+    -localhost no
+
+sleep 2
+
+echo "Starting noVNC on port ${NOVNC_PORT:-6080}..."
+websockify --web=/usr/share/novnc/ ${NOVNC_PORT:-6080} localhost:5901 &
+
+echo ""
+echo "============================================"
+echo "VNC server running on port 5901"
+echo "noVNC web interface: http://localhost:${NOVNC_PORT:-6080}/vnc.html"
+echo "============================================"
+echo ""
+
+# Keep the script running
+tail -f /root/.vnc/*.log