Restructure cistech-tunnel to match rego-tunnel pattern

- build/: Dockerfile + entrypoint.sh (base image with VNC/noVNC)
- shared/: Runtime scripts mounted into container
  - xstartup: VNC startup, launches openconnect-vpn in xterm
  - openconnect-vpn: Main VPN script with menu, auto-connect, watchdog
- Removed source/ folder (replaced by build/)
- Updated docker-compose.json with proper volume mounts
- Changed port to 6080 (noVNC default)

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

apps/cistech-tunnel/config.json

@@ -4,7 +4,7 @@
     "available": true,
     "short_desc": "Cistech VPN client container with noVNC.",
     "author": "alexz",
-    "port": 6902,
+    "port": 6080,
     "categories": [
         "utilities",
         "network"