feat: battery heater overlay on drive detail charts

[vide]

Summary

• Adds Grafana-style annotation bands on Power profile and Battery level charts in Drive Details to highlight periods where battery pre-heating was active
• Parses battery_info.battery_heater from the TeslaMate API drive detail positions
• Contiguous heater-on periods are merged into single annotation ranges
• Rendered as subtle orange semi-transparent bands with thin edge lines

Changes

• DriveModels.kt: Added DriveBatteryInfo model with battery_heater field; added batteryInfo to DrivePosition
• ChartDrawUtils.kt: Added AnnotationRange data class and drawAnnotationRanges() drawing function
• OptimizedLineChart.kt: Added annotationRanges parameter, drawn behind the data line
• FullscreenLineChart.kt: Threaded annotationRanges through to the underlying chart and fullscreen overlay
• DriveDetailScreen.kt: Computes heater ranges from positions, passes to Power and Battery chart cards

Test plan

• Open a drive where battery pre-heating occurred (e.g. drive 7135) — verify orange annotation bands appear on Power and Battery charts
• Open a drive without heater activity — no annotations should appear
• Tap fullscreen on an annotated chart — annotations visible in landscape mode
• Cross-chart sync still works (tap one chart, all charts show synchronized tooltip)

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