Fix Amplify environment variable configuration

- Add amplify.yml for proper build configuration
- Update next.config.ts to expose YOUTUBE_API_KEY env var
- This should fix the issue with secrets not being available in production

🤖 Generated with [Claude Code](https://claude.ai/code)

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

amplify/auth/resource.ts

@@ -1,11 +1,11 @@
-import { defineAuth } from '@aws-amplify/backend';
-
-/**
- * Define and configure your auth resource
- * @see https://docs.amplify.aws/gen2/build-a-backend/auth
- */
-export const auth = defineAuth({
-  loginWith: {
-    email: true,
-  },
-});
+import { defineAuth } from '@aws-amplify/backend';
+
+/**
+ * Define and configure your auth resource
+ * @see https://docs.amplify.aws/gen2/build-a-backend/auth
+ */
+export const auth = defineAuth({
+  loginWith: {
+    email: true,
+  },
+});