Chart adjustments

[MARMdeveloper]

Summary

Improves Y-axis label rendering in all line charts. Labels now show meaningful, non-repeating values and include decimals only when the data range is too small to differentiate values without them. Also adds the maximum value label at the top of the chart.
closes #202

Changes

ChartDrawUtils.kt

• drawYAxisLabels: now renders 5 labels (including upper grid line) instead of 4
• Labels use %.0f format by default, switching automatically to %.1f when any two adjacent labels would otherwise display the same integer value
• All labels are now positioned above its grid line to show equal space between them and not to overlap with data line when it start at (or near) max value.

ChargeDetailScreen.kt and DriveDetailScreen.kt — BatteryChartCard

• Y axis now auto-fits to the nearest multiple of 10 above and below the actual battery level range, instead of a fixed 0–100 range
• This makes the charge curve visually clearer when the battery level change is small (e.g. charging from 33% to 42%)
• For large charges/discharges the visual aspect is the same