Replace grep '[g-zG-Z]' with list_has_domains() that filters out
IPv4 (digits/dots/slashes) and IPv6 (hex/colons/slashes) patterns,
then checks if anything remains. This correctly handles IPv6 IP-only
lists where hex digits a-f caused false positive domain detection.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>