Replaces the old orientation-based strip nesting (TryOrientation,
SelectStripItemIndex, EstimateStripDimension, ShrinkFill helpers) with
a call to IterativeShrinkFiller.Fill for multi-quantity items, plus a
RemnantFinder-based PackArea pass for singles and leftovers.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>