Re-exported for integration tests so they hash reusable-cache roots through
the exact production path (dunce canonicalization + platform path-identity
bytes) rather than an approximation that diverges on Windows.
Run the full fallow CLI: parse argv, dispatch the selected command, and
return the process exit code. This is the crate’s single entry point; the
fallow binary and the multicall fallow-multicall binary both delegate
here so there is exactly one clap tree and one dispatch path.