Sketch on chamfer UI (#3918)

* sketch on chamfer start

* working

* step app from getting in weird state when selection face to sketch on

* sketch on chamfer tests

* clean up

* fix test

* fix click selections for chamfers, add tests

* fixture setup (#3964)

* initial break up

* rename main fixture file

* add more expect state pattern

* add fixture comment

* add comments to chamfer function

* typos

* works without pipeExpr

src/lang/modifyAst.test.ts

@@ -400,7 +400,7 @@ const sketch001 = startSketchOn(part001, seg01)`)
       ast,
       sketchPathToNode,
       extrudePathToNode,
-      'end'
+      { type: 'cap', subType: 'end' }
     )
     if (err(extruded)) throw extruded
     const { modifiedAst } = extruded