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/sketch_face_tests.rs

@@ -75,9 +75,10 @@ fn explicit_rebind_preserves_geometry_dimensions_context_and_one_undo() {
 #[test]
 fn unsupported_face_has_explicit_fixed_alternative_and_no_live_projection() {
     let mut s = Session::default();
-    run(&mut s, "solid.box", json!({"length":10,"width":10,"height":10,"body_name":"Base"}));
-    // The tops of two joined boxes merge into one face that no single construction owns.
-    run(&mut s, "solid.box", json!({"length":10,"width":10,"height":10,"corner":[10,0,0],"operation":"join"}));
+    // A top half Offset Face raised: no construction certificate and no exact history name yet.
+    run(&mut s, "solid.box", json!({"length":40,"width":30,"height":20,"body_name":"Base"}));
+    run(&mut s, "solid.split_face", json!({"faces":[[10,15,20]],"plane":{"origin":[20,0,0],"normal":[1,0,0]}}));
+    run(&mut s, "solid.offset_face", json!({"faces":[[10,15,20]],"distance":5}));
     let mut pick = top_pick(&s, "Base");
     let before = s.doc.to_json();
     let error = s.execute("sketch.create", &json!({"plane":pick})).unwrap_err();