InitCell decode (PortalFlags.PortalSide=0x2) + a swept-pose A8CellAudit comparison
(O=centroid, A=winding-corrected PortalSide, B=opposite) over the real flap cells.
A is IDENTICAL to O at every pose/every portal — the (Flags&2)==0 boolean convention
makes the dat PortalSide sense equal to our centroid sense, so swapping is a no-op
and cannot fix the flap. B culls true-interior poses (wrong polarity). Conclusion:
the flap is NOT the side-test sense — it's the 3rd-person camera eye crossing an
interior portal plane while FindCameraCell still roots in the cell; ANY plane-side
test culls there. No production code changed (no no-op shipped).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>