Add tests for areas of container behaviour not previously exercised:
- crond is running (not just that the crontab file is valid)
- Logrotate config is installed at /etc/pihole/logrotate
- Default DNS upstreams (8.8.8.8/8.8.4.4) applied when none configured
- Web interface accessible at /admin/ (default port and custom port)
- /pihole.docker.tag build metadata file is present
- macvendor.db is present and configured in FTL
- FTL is running as the pihole user (validates DNSMASQ_USER default)
- Capabilities are applied to pihole-FTL (validates fix_capabilities)
- WEBPASSWORD_FILE reads the web password from a Docker secret
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Adam Warner <me@adamwarner.co.uk>
