Transform flat scrolling meter list into grouped view showing one card
per unique meter with:
- Consumption history tracking and delta from previous reading
- Trend sparkline visualization (color-coded for normal/elevated/spike)
- Consumption rate calculation (units/hour over 30-min window)
- Cards update in place instead of creating duplicates
- Alert sound only plays for new meters
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
