Rounds out expansion (host discovery, virtual hosts, screenshots, WAF):
- host_discovery: naabu liveness sweep marks IpAddress.is_alive for
ip_range/asn; port_scan then deep-scans only live hosts
- vhost: ffuf Host-header bruteforce (domain, opt-in) -> vhost-only
Subdomains that http_probe then picks up
- screenshot: httpx headless chromium -> HttpAsset.screenshot_path under
a scan_media volume
- waf_detect: wafw00f fingerprints WAFs -> HttpAsset.waf
All config-driven (ExpansionConfig) with proxy / user-agent / headers +
per-tool custom args threaded through. Adds ffuf, chromium and wafw00f to
the worker image and a scan_media volume.
