expand_volatile_subnets() iterated the whole volatile_ips/ directory and
re-resolved every saved entry as a domain, never removing ones whose domain
was no longer in the .list. As a result, a domain removed from a list kept
re-injecting its (stale) IPs into the table forever — on igw this had
accumulated ~40 stale domains in web-bypass plus claude.ai/anthropic in ai,
shadowing the dedicated fr/claude.ai group.

Pass the current list file to expand_volatile_subnets and prune volatile_ips
entries whose domain is absent from the list before resolving.
Co-Authored-By: Claude <noreply@anthropic.com>