Moves the plot series collection, color palette, retention constants, and
the ~80-line TrackPlotPoints reconciliation (history + retained synthetic
points + current value, de-duplicated by timestamp and pruned to the
retention window) out of the view model into a focused, unit-testable
collaborator. The view model keeps a thin PlotSeries pass-through and
delegates Track/Reset/RefreshSeriesColor. Behavior is unchanged.
Adds 8 tests covering selection add/remove, history+current merge, timestamp
de-duplication, Fahrenheit conversion, reset, and pen-color application.
193 tests pass (was 185).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
JMR-devandClaude Opus 4.8
4e5e0961d8