Geometry, nesting and import code now call PortableMath instead of
System.Math for Sin, Cos, Tan, Atan, Atan2, Asin and Acos (Core, Engine,
IO, Data; 269 calls in 64 files). A test fails if those projects call the
runtime's trig again.
With the runtime's trig, Windows and Linux disagreed in the last bit at
non-quarter angles and the same job could nest differently: the
learned-angle nests (a cross fixture) placed 23 parts in Strip on Windows
and 28 on Linux. Now every Engine.Tests pin gives the same layout on both
(3600 passing on Linux and on DesktopPC), Linux layouts are unchanged, and
the learned-angle rows are re-pinned to the shared layouts, which pass the
overlap and work-area checks, and run on every platform again.
Fixes Project Memory 518f3b58.
Extract the pure world-space position/tangent math from the WinForms
cut-direction arrow renderer into Core (ContourSampler), keeping screen
conversion, arrowheads, and the per-move display policy in the view.
Add a contour-wide arclength scheduler (RingMoves) for measurement use:
distance carries across segment boundaries, short segments are never
omitted, and the closing vertex is not duplicated. Characterization
tests pin the arrow policy (counts, short-move skipping, CW/CCW and
full-circle sweeps, subprogram offsets, suppressed/rapid moves,
incremental mode) and the scheduler's start-vertex invariance.
aj