Add temporary Shopify OAuth install routes

/shopify/install  → redirects to Shopify OAuth
/shopify/callback → exchanges code for access token and displays it

To be removed after token is captured.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

routes/web.php

@@ -1,7 +1,12 @@
 <?php
 
+use App\Http\Controllers\ShopifyInstallController;
 use Illuminate\Support\Facades\Route;
 
 Route::get('/', function () {
     return redirect('/dashboard', 301);
 });
+
+// Temporär: einmalige Shopify OAuth-Installation
+Route::get('/shopify/install',  [ShopifyInstallController::class, 'install']);
+Route::get('/shopify/callback', [ShopifyInstallController::class, 'callback']);