Split Face (FusionSplitFaceCommand): a timeline feature dividing the picked faces where a plane, another body's face (its surface extended) or a sketch's curves meet them, through kernel::split_faces; the solid is unchanged and the pieces take the face's name with #k. Rebase fixes: duplicate Chamfer and Combine specs; the Delete selection's face test expects Delete Face's refusal

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL

crates/engine/src/lib.rs

@@ -430,6 +430,8 @@ mod delete_face_tests;
 #[cfg(test)]
 mod extent_tests;
 #[cfg(test)]
+mod split_face_tests;
+#[cfg(test)]
 mod tests;
 #[cfg(test)]
 mod thread_tests;