A tool window for the rectangular sketch pattern (#799)

sketch.pattern.rectangular gets a tool window with both quantities and spacings and an optional direction, instead of a click flow with a fixed count.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

crates/ui-egui/src/canvas.rs

@@ -101,9 +101,10 @@ pub fn anchor(app: &SolveApp, d: &Dialog) -> Option<(Vec3, Option<Vec3>)> {
         Kind::SketchModify(crate::sketch_modify_ui::Mod::Move { .. }) => {
             (at, app.session.active_sketch.and_then(|id| st.sketch(id)).and_then(|ss| ss.plane.x.normalized()))
         }
-        // Offset's arrow is already computed above, per picked curve; keep it rather than the
-        // default below.
-        Kind::SketchModify(_) => (at, normal),
+        // The rectangular pattern's spacing grows along the direction it was given, which the
+        // module works out per variant. Offset's arrow is already computed above, per picked
+        // curve, and `arrow` returns None for it so that one stands.
+        Kind::SketchModify(_) => (at, crate::sketch_modify_ui::arrow(app, d).or(normal)),
         _ => (at, None),
     })
 }