--autonest can now use more than one physical sheet. The first layout
replaces the target plate's parts, further layouts are inserted as new
plates after it, and --stock offers explicit sheet sizes (with optional
costs) built from the target's spacing, quadrant and clamp rail.
NestPipelineCommit gains ApplyToPlates for callers without a
PlateManager. Per-sheet results and overlap checks cover every
committed plate.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>