Fillet and chamfer of one edge ending on curved, slanted or several faces (#646)

A single edge's blend no longer needs a plane square to the edge at each end. Straight edges: each rail ends where it reaches the end face's surface, the side edges there are shortened or continued along their line or circle, and the blend ends where its cylinder or chamfer plane meets that surface (a fitted curve checked against both). A chamfer may end across two faces. Curved edges: at a slanted or curved end the rolling ball runs on past the end and the strip is cut back where it meets that face. A straight edge running smoothly into a bend or rounded corner is blended along its whole smooth chain. Rolling-ball fixes: smooth chains follow edges stored against their curve, the ball touches only the faces of the edges it rolls along, the seam normal at a joint comes from the face there, and each strip is fitted with neighbouring sections at its own spacing.

Action matrix: edge.fillet 83.6% -> 93.0%, edge.chamfer 82.6% -> 93.3% (697 new passes, no regressions); reference tests 76/76.

Fixes #556

Co-Authored-By: Claude Opus 5.5 <[email protected]>

apps/solidcraft-cli/tests/action_matrix.rs

@@ -980,7 +980,6 @@ fn rectangle(plane: Value, p0: [f64; 2], p1: [f64; 2]) -> [Value; 3] {
 }
 
 #[test]
-#[ignore = "fails until #556 is fixed"]
 fn a_fillet_or_chamfer_on_one_edge_ending_at_a_cylinder() {
     for (cmd, size) in [("solid.fillet", "radius"), ("solid.chamfer", "distance")] {
         reproduces(