fix(cdk): migrate TypeScript config for TS 7 moduleResolution

Use Node16 module/moduleResolution and explicit .js relative import
so npm run synth succeeds under TypeScript 7.0.2.

infra/cdk/app.ts

@@ -1,5 +1,5 @@
 import * as cdk from 'aws-cdk-lib';
-import { DeployDevStack } from './deploy-dev-stack';
+import { DeployDevStack } from './deploy-dev-stack.js';
 
 const app = new cdk.App();
 

infra/cdk/tsconfig.json

@@ -1,9 +1,9 @@
 {
   "compilerOptions": {
     "target": "ES2022",
-    "module": "commonjs",
+    "module": "Node16",
     "lib": ["ES2022"],
-    "moduleResolution": "node",
+    "moduleResolution": "Node16",
     "strict": true,
     "noImplicitAny": true,
     "strictNullChecks": true,