Change unknown feature error to warning

Co-authored-by: kategengler <444218+kategengler@users.noreply.github.com>

Author: Copilot

index.js

@@ -1,6 +1,7 @@
 'use strict';
 
 const SilentError = require('silent-error');
+const chalk = require('chalk');
 
 const FEATURES = require('./features');
 const getConfigPath = require('./utils').getConfigPath;
@@ -42,8 +43,10 @@ module.exports = {
     let keys = Object.keys(features);
     keys.forEach((key) => {
       if (FEATURES[key] === undefined) {
-        throw new SilentError(
-          `Unknown feature "${key}" found in config/optional-features.json`
+        console.warn(
+          chalk.yellow(
+            `Warning: Unknown feature "${key}" found in config/optional-features.json`
+          )
         );
       } else if (features[key] !== null && typeof features[key] !== 'boolean') {
         throw new SilentError(

tests/optional-features-test.js

@@ -52,8 +52,23 @@ QUnit.module('@ember/optional-features', (hooks) => {
     return projectRoot.dispose();
   });
 
-  QUnit.test('it throws on invalid key', (assert) => {
-    assert.throws(() => buildAddon({ foo: true }), /Unknown feature "foo"/);
+  QUnit.test('it warns on invalid key', (assert) => {
+    let originalWarn = console.warn;
+    let warningMessage = null;
+    console.warn = (msg) => {
+      warningMessage = msg;
+    };
+    try {
+      let addon = buildAddon({ foo: true });
+      assert.ok(
+        warningMessage && warningMessage.includes('Unknown feature "foo"'),
+        'Should warn about unknown feature'
+      );
+      // The addon should still initialize successfully
+      assert.ok(addon.config, 'Addon should be initialized');
+    } finally {
+      console.warn = originalWarn;
+    }
   });
 
   QUnit.test('it throws on invalid value', (assert) => {