Adds path reference for local function bundling

Ensures direct file location support for consistent build outputs

Author: pavinthan

src/pages/[platform]/build-a-backend/functions/custom-functions/index.mdx

@@ -114,6 +114,8 @@ import { defineFunction } from "@aws-amplify/backend";
 import { DockerImage, Duration } from "aws-cdk-lib";
 import { Code, Function, Runtime } from "aws-cdk-lib/aws-lambda";
 
+const functionDir = path.dirname(fileURLToPath(import.meta.url));
+
 export const sayHelloFunctionHandler = defineFunction(
   (scope) =>
     new Function(scope, "say-hello", {