Sketch on cut walls, chamfers, pattern copies, join-merged sides and split faces (#625)

A flat face that no construction certificate names on its own now attaches by its exact history name (a new lineage face certificate): cut walls and floors, chamfer faces, each pattern or mirror copy, side walls a Join merged, and the pieces a later feature split a face into. Construction certificates still come first; a seed keeps its certificate when it is patterned. Two flush extrudes of one outline joined end to end keep their exact history in the prism boolean. Face sketch 52% -> 71%, offset plane 52% -> 71%, press-pull/extrude from face 41% -> 60% in the action matrix; baseline blessed.

Fixes #491, fixes #492, fixes #493, fixes #557.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/cmd/stacked_face_tests.rs

@@ -67,20 +67,13 @@ fn sketch_and_offset_plane_on_the_top_face_of_a_face_sketched_extrude() {
                     assert!((plane.origin.z - 20.).abs() < 1e-9 && (plane.normal().z - 1.).abs() < 1e-9, "{case}: {plane:?}");
                     s.execute("construct.plane.offset", &json!({"base": {"face": top}, "offset": 5, "name": "Above"}))
                         .unwrap_or_else(|e| panic!("{case}: {e}"));
-                    // The second extrude's flat side is an exact source too, unless a full-face
-                    // Join merged it with the first extrude's side: that face belongs to neither,
-                    // so it offers the explicit fixed plane with a readable reason.
+                    // The second extrude's flat side attaches too, also where a full-face Join
+                    // merged it with the first extrude's side (#491): that face is known by its
+                    // exact history name.
                     if !circle {
                         let side = if full { [40., 20., 15.] } else { [30., 20., 15.] };
-                        let params = json!({"plane": {"face": side}, "name": "Side"});
-                        if full && operation == "join" {
-                            let error = s.execute("sketch.create", &params).unwrap_err().to_string();
-                            assert!(error.contains("merged") && error.contains("fixed:true"), "{case}: {error}");
-                            run(&mut s, "sketch.create", json!({"plane": {"face": side, "fixed": true}, "name": "Side"}));
-                        } else {
-                            s.execute("sketch.create", &params).unwrap_or_else(|e| panic!("{case} side: {e}"));
-                            assert!((healthy(&s, "Side").normal().x - 1.).abs() < 1e-9, "{case}");
-                        }
+                        s.execute("sketch.create", &json!({"plane": {"face": side}, "name": "Side"})).unwrap_or_else(|e| panic!("{case} side: {e}"));
+                        assert!((healthy(&s, "Side").normal().x - 1.).abs() < 1e-9, "{case}");
                         run(&mut s, "sketch.finish", json!({}));
                     }
                     s.refresh();