Widget displays:
- systemSmall: calorie ring + "X left" text
- systemMedium: ring + "Calories" / "X of Y" / "X remaining"
- accessoryCircular: gauge ring for lock screen
- accessoryInline: "🔥 845 / 2000 cal" text for lock screen
- accessoryRectangular: linear gauge + calorie count
Data flow: main app writes totalCalories + calorieGoal to
UserDefaults on each loadTodayData(), then calls
WidgetCenter.shared.reloadAllTimelines(). Widget reads on
15-minute refresh cycle.
Note: currently uses standard UserDefaults (same app container).
For production, migrate to App Group UserDefaults so widget
process can read the data. Requires Xcode App Group setup.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
