fix(charts): select the nearest original time-series point

Record usage points open original source events. The retained-record browser journey exposed overlapping hit circles selecting event20 at event13’s visual centre on a phone. Extend existing timeSeries/FigureView with selectable point semantics and onPointSelect(index); shared hover/click resolves the nearest visible mark and Enter/Space activates the focused mark. Passive figures retain their behavior. No drawing fork or new point format.

Run ID: run_d6a451eac952679e802d772b0104ffcb