Class-A surfacing 3/3: blend curves, curved-edge fillets, the G2 corner and continuity analysis (#1642)

Thanks @midasdf.

crates/sketch/src/freeform_offset.rs

@@ -137,7 +137,9 @@ impl H {
         let (points, weights) = match *seg {
             Seg2::Line { a, b } => (vec![a, b], vec![1.0; 2]),
             Seg2::Cubic { p0, p1, p2, p3 } => (vec![p0, p1, p2, p3], vec![1.0; 4]),
-            Seg2::Bezier { n, p } if (1..=7).contains(&n) => (p[..=usize::from(n)].to_vec(), vec![1.0; usize::from(n) + 1]),
+            Seg2::Bezier { n, p } if (1..=solidcraft_geom::MAX_BEZIER_DEGREE as u8).contains(&n) => {
+                (p[..=usize::from(n)].to_vec(), vec![1.0; usize::from(n) + 1])
+            }
             Seg2::Conic { a, apex, b, w } if w.is_finite() && w > 0.0 => (vec![a, apex, b], vec![1.0, w, 1.0]),
             _ => return Err(bad("unsupported exact free-form offset piece")),
         };