V3 deterministic CSV column-selection capability pack. By-value connector composition (service_kind=cli, no separate ingredient): the local csvcut CLI returns selected columns from one trusted local CSV path via the csv.select catalog operation. This is the reproducible csvkit-backed fallback for qsv select while qsv lacks a Debian-stable package. Path-based by design: selected CSV rows are stdout value output, so this operation does not combine file_ref materialization with stdout capture. Requires csvkit on PATH (Debian/Ubuntu: apt install csvkit; Python environments: pip install csvkit). Local and no-egress.