Add diagonal_win.dsn: a 45-degree pin-to-pin net with a keepout placed inside the
diagonal's bounding box but clear of the true thin copper. Orthogonal routing
connects it with a Manhattan-length staircase (1600000); diagonal routing
replaces that with a single 45-degree trace at the ideal hypotenuse length
(1131371) -- a 29% reduction -- DRC-clean via the search tree and via an
independent reconstruction of the emitted 45-degree copper's clearance octagon.
test_exact_clearance_is_load_bearing shows the keepout overlaps the coarse
bounding box but not the exact octagon, so the exact clearance (not the box) is
what lets the diagonal route. Determinism, endpoints-on-pads, valid SES, and
diagonal-off-equals-orthogonal (additive, over four fixtures) are covered.
Ryan Malloy
accec686f8