V3 deterministic barcode/QR image scan capability pack. By-value connector composition (service_kind=cli, no separate ingredient): the local zbarimg CLI reads one trusted local image path and returns decoded barcode payload text via the image.scan_barcode catalog operation. This is the read-side complement to the existing qrencode pack. The operation is path-based because decoded payloads are stdout value output; it does not combine file_ref materialization with value capture. Requires zbarimg on PATH (Debian/Ubuntu: apt install zbar-tools). Local and no-egress.