0.4.0

Breaking: requires an ES2020-capable JavaScript engine (Node.js 12 or newer) and the Amber packages that share that floor; the es6-promise polyfill is no longer shipped.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

package.json

@@ -2,7 +2,7 @@
   "name": "@ambers/prof-stef",
   "title": "Prof Stef",
   "description": "Smalltalk tutorial \"Prof Stef\" for Amber",
-  "version": "0.3.1",
+  "version": "0.4.0",
   "homepage": "https://amber-lang.net/learn.html",
   "author": {},
   "repository": {