Function color_enabled 

pub fn color_enabled() -> bool

Whether color output should be emitted right now.

Priority: explicit override (--ansi/--no-ansi) wins; then NO_COLOR / FORCE_COLOR env vars (the industry conventions from https://no-color.org/); finally fall back to stderr().is_terminal(). Help output is written to stderr by the hand-rolled helps and to stdout by the derive; both are checked so CI log viewers (which render ANSI but have no stdout TTY) still get color when invoked with --ansi or FORCE_COLOR=1.