consider True Color support

[trentm]

In internal/ansipainter consider True Color support. Would it add much?

See https://gist.github.com/XVilka/8346728 and https://github.com/chalk/chalk and https://github.com/gookit/color

[trentm]

• consider https://github.com/muesli/termenv for ANSI color handling.
  Supports truecolor and degradation. Supports templates which might be
  useful for config-based custom styling.