DefaultPlateFiller runs its search in a canonical (MBR-axis-aligned)
copy of the drawing. Intermediate progress reports — the Nesting
Progress dialog, PlateView's active-parts overlay — were showing that
transient canonical orientation instead of the drawing's real one.
FillContext.OriginalDrawing carries the pre-canonicalization drawing
through the pipeline; ReportProgress rebinds reported parts to it via
CanonicalFrame.RebindToOriginal before they reach the UI. Uses a
shallow list copy rather than per-part Part.Clone() — Clone() re-derives
its target rotation from BaseDrawing.Program.Rotation + Rotation, which
would double-count the canonical drawing's baked source angle.
aj