Version-locked BIT 4.1.0 release.
Changes:
- Increase default wall thickness to 2.0 mm.
- Rework sliding lids for right-side-up printing, including wedge orientation, label placement, detent groove placement, and 180-degree print rotation.
- Replace sliding-lid detents with matching right-triangle locking detents/cavities that stay off the chamfered rail edge.
- Make G_LID_THICKNESS control sliding panel and rail height when set; otherwise it follows wall thickness.
- Fix side finger cutouts so 100% height reaches through the floor and EXTERIOR cutouts breach sliding rails.
- Add physical validation coverage and sliding-lid regression tests, including a labeled sliding-lid fixture.