fix(cdn): use the expanded cdn value rather than the last one

fixes an issue where cdnBaseUrl is not inheriting from parent project.jsons because it's using the top level config and not the expanded one

Author: e111077

src/playground-project.ts

@@ -833,7 +833,6 @@ const fetchProjectConfig = async (
 
   return {
     ...result,
-    cdnBaseUrl: config.cdnBaseUrl,
   };
 };
 
@@ -1090,3 +1089,6 @@ const playgroundFilesDeepEqual = (
   }
   return true;
 };
+
+// Export functions for testing
+export { fetchProjectConfig, expandProjectConfig };

src/test/expanded-config_test.ts

@@ -0,0 +1,62 @@
+import { expandProjectConfig } from '../playground-project.js';
+import { assert } from '@esm-bundle/chai';
+
+// Removed MockResponse interface as it's not needed.
+
+suite('expandProjectConfig cdnBaseUrl behavior', () => {
+  const originalFetch = globalThis.fetch;
+
+  setup(() => {
+    // Mock fetch to return a parent config when requested
+    globalThis.fetch = async (input: RequestInfo | URL): Promise<Response> => {
+      const url = typeof input === 'string' ? input : input.toString();
+      if (url.endsWith('parent-config.json')) {
+        return {
+          status: 200,
+          json: async () => ({
+            files: {
+              'parent.txt': { content: 'parent content' }
+            },
+            cdnBaseUrl: 'https://parent-cdn.com'
+          }),
+          text: async () => 'parent config'
+        } as Response;
+      }
+      return {
+        status: 404,
+        json: async () => ({}),
+        text: async () => 'Not Found'
+      } as Response;
+    };
+  });
+
+  teardown(() => {
+    // Restore original fetch
+    globalThis.fetch = originalFetch;
+  });
+
+  test("should use parent's cdnBaseUrl when child does not define one", async () => {
+    const childConfig = {
+      files: {
+        'child.txt': { content: 'child content' }
+      },
+      extends: 'https://example.com/parent-config.json'
+    };
+
+    const result = await expandProjectConfig(childConfig, 'https://example.com/');
+    assert.equal(result.cdnBaseUrl, 'https://parent-cdn.com');
+  });
+
+  test("should prefer child's cdnBaseUrl over parent's when defined", async () => {
+    const childConfig = {
+      files: {
+        'child.txt': { content: 'child content' }
+      },
+      cdnBaseUrl: 'https://child-cdn.com',
+      extends: 'https://example.com/parent-config.json'
+    };
+
+    const result = await expandProjectConfig(childConfig, 'https://example.com/');
+    assert.equal(result.cdnBaseUrl, 'https://child-cdn.com');
+  });
+});