use released optional-features and document current min node

Author: ef4

package.json

@@ -190,7 +190,7 @@
     "@glimmer/component": ">= 1.1.2"
   },
   "engines": {
-    "node": ">= 18.*"
+    "node": ">= 20.19"
   },
   "ember-addon": {
     "after": "ember-cli-legacy-blueprints",

pnpm-lock.yaml

@@ -24,7 +24,7 @@
   },
   "devDependencies": {
     "@babel/core": "^7.24.4",
-    "@ember/optional-features": "2.3.0-alpha.0",
+    "@ember/optional-features": "^2.3.0",
     "@ember/string": "^3.0.1",
     "@ember/test-helpers": "^3.3.0",
     "@ember/test-waiters": "^3.1.0",

smoke-tests/app-template/package.json

@@ -35,7 +35,7 @@
     "@babel/runtime": "^7.27.1",
     "@babel/plugin-transform-runtime": "^7.27.1",
     "@babel/eslint-parser": "^7.27.1",
-    "@ember/optional-features": "2.3.0-alpha.0",
+    "@ember/optional-features": "^2.3.0",
     "@ember/string": "^4.0.1",
     "@ember/test-helpers": "^5.2.2",
     "@ember/test-waiters": "^4.1.0",