@spec extract(binary(), String.t()) :: {:ok, non_neg_integer()} | {:error, term()}

Extract a .tgz tarball into a destination directory.

Strips the package/ prefix that npm tarballs use. Returns {:ok, file_count}.

@spec fetch_and_extract(String.t(), String.t(), String.t()) ::
  {:ok, non_neg_integer()} | {:error, term()}

Download a tarball, verify its integrity, and extract to a directory.

Returns {:ok, file_count} or {:error, reason}.

@spec verify_integrity(binary(), String.t()) :: :ok | {:error, :integrity_mismatch}

Verify SHA-512 integrity of a binary against an SRI hash.