Auto-detects format when --format is empty: pretty when stdout is a TTY,
tsv when piped/redirected. JSON emits an array of {ip, found} objects;
CSV adds an 'ip,status' header row.
New package for matching IPs against cohort lists (single IPs and
networks, in separate files or combined) with inbound/outbound/whitelist
semantics. Supports the bitwire-it/ipblocklist data shape out of the box
and is meant to be paired with gitshallow or httpcache for periodic
refresh. Includes README, ipcohort-contains CLI, and tests.
