re_time_ruler

Time ruler primitives shared by the time panel and time-aware views.

Exposes:

• [TimeRangesUi] — the linear-piecewise time↔screen mapping used by the time panel, with optional gap collapsing between linear time segments.
• [paint_time_ranges_and_ticks] — renders tick marks and labels for one or more time segments inside a given x-range.

The crate has no opinion on how the user pans and zooms — callers wire those up themselves. The helpers [TimeRangesUi::pan] and [TimeRangesUi::zoom_at] return new TimeViews that the caller can apply.