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

Thanks @midasdf.

crates/io/src/dxf_out.rs

@@ -667,7 +667,7 @@ mod tests {
         assert!(degree_2(&conic(2.0), Some(vec![1.0, 2.0, 1.0])));
         assert!(degree_2(&conic(1.0 - 1e-9), Some(vec![1.0, 1.0 - 1e-9, 1.0])));
         // A quintic piece: six control points and twelve knots.
-        let mut q = [Vec2::ZERO; 8];
+        let mut q = [Vec2::ZERO; solidcraft_geom::MAX_BEZIER_CTRL];
         for (i, s) in q.iter_mut().enumerate() {
             *s = Vec2::new(i as f64, (i * i) as f64);
         }

crates/io/src/lib.rs

@@ -864,6 +864,7 @@ mod tests {
                 body: None,
                 style: Default::default(),
                 fit: Default::default(),
+                corner: Default::default(),
             },
             None,
         )
@@ -948,6 +949,7 @@ mod tests {
                 body: None,
                 style: Default::default(),
                 fit: Default::default(),
+                corner: Default::default(),
             },
             None,
         )