refactor: remove createScope helper

Drop the exported helper and finish migrating call sites. Revert incidental context/for/include/layout churn so behavior matches mainline aside from the removal. Trim duplicate e2e and heavy Object.prototype loops in registry tests.

Co-authored-by: Cursor <[email protected]>

src/context/context.spec.ts

@@ -138,11 +138,6 @@ describe('Context', function () {
       ctx.push({ foo: [] })
       return expect(ctx.getSync(['foo', 'reduce'])).toEqual(undefined)
     })
-    it('should return undefined for typical Object.prototype properties (e.g. constructor, valueOf)', function () {
-      ctx.push({ obj: {} })
-      expect(ctx.getSync(['obj', 'constructor'])).toEqual(undefined)
-      expect(ctx.getSync(['obj', 'valueOf'])).toEqual(undefined)
-    })
     it('should return undefined for function prototype property', function () {
       function Foo () {}
       Foo.prototype.bar = 'BAR'