Document Sanctum API token integration for Laravel 12

Added instructions for integrating Laravel Sanctum's API token authentication with Tenancy for Laravel in Laravel 12, including middleware configuration.

source/docs/v3/integrations/sanctum.blade.md

@@ -38,3 +38,37 @@ To use the `sanctum.csrf-cookie` route in both the central and the tenant apps:
 3. Remove `Sanctum::ignoreMigrations()` from your `AuthServiceProvider`'s `register()` method
 4. Remove `'routes' => false` from the `sanctum.php` config
 5. Add the `'universal'` middleware to the `sanctum.csrf-cookie` route in your `routes/tenant.php`
+
+### Sanctum API Token Integration with Laravel 12 {#sanctum-api-token-integration-laravel-12}
+
+When integrating **Laravel Sanctum’s API token authentication** with **Tenancy for Laravel** in **Laravel 12**, you may encounter an issue where:
+
+```php
+$request->user(); // returns null
+```
+even though you have correctly applied the auth:sanctum middleware.
+
+This happens because, in Laravel 12, middleware registration is handled via the new bootstrap/app.php file, and the tenancy initialization middleware must run before Sanctum’s authentication middleware in the API middleware stack.
+
+To resolve this, update your bootstrap/app.php as follows:
+```php
+use App\Http\Middleware\InitializeTenancyBySubDomain;
+use Illuminate\Foundation\Configuration\Middleware;
+
+return Application::configure(basePath: dirname(__DIR__))
+    ->withMiddleware(function (Middleware $middleware): void {
+        $middleware->web([]);
+
+        // 👇 Important: Prepend tenancy middleware before Sanctum runs
+        $middleware->api(prepend: [
+            InitializeTenancyBySubDomain::class,
+        ]);
+    })
+    ->create();
+```
+
+With this change, the tenancy context initializes before Sanctum authenticates the user, allowing $request->user() to resolve correctly to the authenticated tenant user.
+
+Note: In earlier Laravel versions (≤11), middleware order was managed in app/Http/Kernel.php.
+Since Laravel 12 replaces that with bootstrap/app.php, explicit ordering via withMiddleware() is now required.
+