Validate that a parsed hitlist is non-empty, collect the IP versions it uses,
and optionally shuffle it. Shared by get_hitlist (file) and
get_targets (inline --target list).
Build a hitlist from a comma-separated list of target addresses (e.g. from the
--target CLI flag), as an alternative to a hitlist file. The targets are
treated exactly like a hitlist containing those addresses.
Parse one USC/ISI ANT hitlist row into ranked candidate addresses.
The block length selects the IP version: 8 hex digits is an IPv4 /24,
12 hex digits is an IPv6 /48.