provision: show output on screen via qt_shell, capture stderr

- on_start.sh runs provision through qt_shell for on-screen display
- provision_wrapper.sh redirects stderr to stdout so errors are visible
- provision.sh: SSH setup before WiFi wait, verbose echo output,
  sleep on failure so messages are readable

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

system/clearpilot/provision_wrapper.sh

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec bash /data/openpilot/system/clearpilot/provision.sh 2>&1