rego-tunnel: move all scripts to dynamic mounts

- Move entrypoint.sh from build/scripts/ to shared/
- Create startup-vnc.sh in shared/ (was base64-encoded in Dockerfile)
- Remove baked-in scripts and CMD from Dockerfile (keep vnc.service unit only)
- Entrypoint now: chmod +x all shared scripts, symlinks startup-vnc.sh
  to /opt/scripts/ so systemd vnc.service still finds it
- Fix host watcher: use /bin/bash in ExecStart for permission resilience
- Bump tipi_version to 7

All scripts are now dynamically controlled via volume mounts.

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

apps/rego-tunnel/shared/startup-vnc.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+set -e
+export HOME='/root'
+export USER='root'
+rm -f /tmp/.P1-lock /tmp/.X11-unix/X1 2>/dev/null || true
+rm -rf /tmp/.X*-lock /tmp/.X14-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 &
+tail -f /root/.vnc/*.log