Guide sketch patterns with live previews and editable offsets (#966)

Sketch Mirror, rectangular and circular Pattern, and Offset now show a green live preview that follows the selection and settings; OK commits, Cancel leaves the sketch unchanged. The shared dialogs show the current selection step and source counts, sources can be toggled with Ctrl/Cmd-click, cleared and reselected.

Offsets keep editable driving distance dimensions (One Side, Two Sides, Symmetric) that update the derived curves without moving the source, with undo/redo and save/reopen. Format 19: older files keep their fixed offsets.

New dialog labels in en, zh, ja, de and ko.

Fixes #696. Fixes #517.

crates/ui-egui/src/lib.rs

@@ -111,6 +111,8 @@ mod sketch_drag_ui_tests;
 #[cfg(test)]
 mod sketch_edit_tests;
 mod sketch_families;
+#[cfg(test)]
+mod sketch_guidance_ui_tests;
 pub mod sketch_modify_ui;
 #[cfg(test)]
 mod sketch_modify_ui_tests;