Cleaner workout step names on Garmin and other head units

Workout steps currently carry descriptive names (including the coach's warm-up and cooldown notes), which can crowd out the power/pace target on Garmin devices, especially smaller watches. This would keep step names short and clean on the device (Warmup, Cooldown, short interval labels) and move the coach's notes to the workout description, with an option to control how much text reaches your head unit.