`poseDoorMovingParts` assigned a single euler axis (`group.rotation.y` /
`.x`). The live system was fine because the group's euler stays a clean
(0, y, 0). But the GLB exporter clones the door and decomposes its matrix,
which re-derives a gimbal-flipped euler (x=z=π) for any rotation beyond
±90° — folding panels reach ~158°. The reset to t=0 then only zeroed `.y`,
leaving the π residue on x/z and baking a 180°-flipped rest pose (panels
folded out toward a wrong position even when closed).
Set the full euler triple via `.set()` in every pose branch so the other
two axes are always zeroed, clearing any decomposed residue. Add a
regression test that exports an open folding door and asserts an identity
rest pose for all panels.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>