scaffold laravel 12 backend

composer create-project laravel/laravel + artisan install:api.
sanctum removed (custom session-cookie auth per ai/backend-context).
personal_access_tokens migration + config/sanctum.php deleted.
default .gitignore excludes vendor/, .env, etc - composer install
recreates vendor at setup time.

backend/storage/framework/.gitignore

@@ -0,0 +1,9 @@
+compiled.php
+config.php
+down
+events.scanned.php
+maintenance.php
+routes.php
+routes.scanned.php
+schedule-*
+services.json