- Add _getAnchorPixelPosition method that handles anchors outside
the visible time range by calculating their position along the line
- Update _createAnchor to use robust position calculation
- Update _updateFormationPositionsInPlace to use new method
Previously, anchors would not update when their time coordinate was
outside the visible range (because _chartToPixel returns null).
Lines would update correctly via _getInfiniteLineEndpoints, but anchors
would stay at stale positions.
Now anchors are positioned at the viewport edge when their actual
time coordinate is outside the visible range, keeping them on the line.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
rob
ee199022fa