fix(install): silence shellcheck SC2016 on the intentional $PATH hint

The PATH hint deliberately prints a literal `$PATH` for the user to copy; mark
the line with a scoped `# shellcheck disable=SC2016` so the installer CI lane
passes (shellcheck exits non-zero even on info-level findings).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: gustavobertoi

install.sh

@@ -127,6 +127,7 @@ fi
 case ":${PATH}:" in
 	*":${install_dir}:"*) ;;
 	*) warn "${install_dir} is not on your PATH — add it, e.g.:"
+	   # shellcheck disable=SC2016  # the literal $PATH is intentional in this hint
 	   printf '       export PATH="%s:$PATH"\n' "$install_dir" >&2 ;;
 esac