Fold dialog (SHEET METAL > Fold); configurations and motion study dialogs pass their scenarios

Fold: the bend line (a sketch line), an optional stationary side, Bend Line Position
(centerline, start, end, outside mould line), angle (on the canvas), bend radius (default from
the rule) and flip; live preview and Edit Feature (folds made from two points keep them). Its
own icon; listed after Hem on the SHEET METAL tab and in the timeline.

Configurations: Add Column lists parameters and features to pick, Add Row names the new row
Configuration<N> when no name is typed, bare numbers show with their parameter's unit, the row
name comes before its Activate button, and Enter commits a cell instead of closing the panel.
Motion Study: steps default to the engine's 100, the key's value row is "Value" and Enter there
commits the key (OK makes the study).

Scenarios s22 (fold, flat pattern, DXF; the expected volume is the folded sheet's, the bend
keeping the neutral layer), s23 (configurations) and s24 (motion study) now run.

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

crates/ui-egui/src/workspace.rs

@@ -29,6 +29,7 @@ const SHEET_CREATE: &[&str] = &[
     "FusionSheetMetalFlangeCommand",
     "FusionSheetMetalFlatPatternCmd",
     "FusionSheetMetalHemFlangeCommand",
+    "SheetMetalFoldCmd",
     "ConvertToSheetMetalCmd",
     "FusionCreateNewComponentCommand",
     "Extrude",
@@ -123,6 +124,7 @@ pub fn feature_icon(k: &FeatureKind) -> Option<&'static str> {
     Some(match k {
         FeatureKind::SheetBase { .. } | FeatureKind::SheetContour { .. } | FeatureKind::SheetFlange { .. } => "flange",
         FeatureKind::SheetHem { .. } => "hem",
+        FeatureKind::SheetFold { .. } => "fold",
         FeatureKind::SheetUnfold { refold: false, .. } => "unfold",
         FeatureKind::SheetUnfold { .. } => "refold",
         FeatureKind::SheetConvert { .. } => "convert_sheet",