An arc lead-in meeting a straight window edge tangentially has a double
root at its joint. Rounding split it into two contacts a few 1e-8 apart,
or dropped it so the exact ray fallback reported the joint as an
uncertain contact. Either refused a valid entry, so N26-27U's windows
lost most of their entries and the plate never planned.
Treat a contact within 1e-6 of a joint its boundary passes through as
the joint, and let the exact line fallback skip ray hits at contacts
already recorded. The pinned-hole test now expects the other hole's
nearest entry rather than the fallback both runs used to share.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>