Split Body by a face of a body: FusionSplitBodyCommand tool {body, point}

The Split feature takes an optional face tool (FaceAt, the face through a
point on a named body) and splits with kernel split_body, the tool's
surface extended; otherwise the plane as before. Engine test: a box split
by a cylinder's side into the core and the rest.

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

crates/ui-egui/src/dialogs.rs

@@ -2625,7 +2625,7 @@ pub fn for_feature(app: &SolveApp, id: u64, marker: Option<usize>) -> Option<Dia
             }
             d
         }
-        FeatureKind::Split { body, plane } => {
+        FeatureKind::Split { body, plane, .. } => {
             let mut d = start("FusionSplitBodyCommand")?;
             if let Some(inp) = d.inputs.first_mut() {
                 inp.items = vec![Sel::Body { name: body.clone() }];