Minilints cannot find cargo-license when the Cargo install directory is absent from PATH

## Problem

Use a Rust toolchain reachable on PATH while the user Cargo binary directory is absent from PATH, then run `just minilints` or the standalone minilints interface used by CI. Minilints installs cargo-license into Cargo's default directory and subsequently executes `cargo-license` by name. Installation can succeed but execution still fails because the install directory is not searched.

## Expected behavior

The documented build/check command should provision its declared prerequisites and complete without a manual path workaround.

## Environment

Observed while developing on Apple Silicon macOS at 9753998c5; the affected code is still present in upstream main at 93bd38288. A focused fix and validation are prepared.