The home screen CaloriesCard now uses a circular ring (CustomPainter)
instead of a LinearProgressIndicator. Ring colour is determined by the
user's goal type (lose / maintain / gain) with inverted semantics for
the gain goal — red means undereating, not overeating.
Overflow beyond 100% is shown as a thinner second-lap arc in the same
warning colour. Numbers (logged kcal, goal, remaining/overage) are
displayed both inside the ring and in a stat column to the right.
Adds docs/calorie_ring_color_spec.md with the full colour threshold
specification per goal type.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2a95bcd53c