chore: scaffold Laravel 13 core app

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BCrwHHnGCB5XH968Nxokqw

core/routes/web.php

@@ -0,0 +1,7 @@
+<?php
+
+use Illuminate\Support\Facades\Route;
+
+Route::get('/', function () {
+    return view('welcome');
+});