Regression tests for the XZ plane orientation (#78): a positive extrude from XZ and from an XZ offset plane goes +Y; a format 5 design with XZ sketches, an offset plane and extrudes opens, and resaves, with identical volumes and bounding boxes (#353)

Claude-Session: https://claude.ai/code/session_01RjGw4gA5ZvKrU8MQP6sBgT

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/tests.rs

@@ -145,6 +145,7 @@ mod component_frames;
 mod mirror_planes;
 mod primitive_points;
 mod robustness;
+mod xz_plane;
 
 /// Plan area a round of radius `r` fills at the concave corner `x` where circles (c1, r1) and
 /// (c2, r2) cross: the triangle of its contacts and the corner, less the three circular segments.