test(factories): add missing model factories for app test suite

Enable `HasFactory` on `Environment`, `Project`, `ScheduledTask`, and
`StandaloneDocker`, and add dedicated factories for related models to
stabilize feature/unit tests.

Also bump `visus/cuid2` to `^6.0` and refresh `composer.lock` with the
resulting dependency updates.

tests/Unit/ServerManagerJobSentinelCheckTest.php

@@ -7,7 +7,6 @@ use App\Models\InstanceSettings;
 use App\Models\Server;
 use Illuminate\Support\Carbon;
 use Illuminate\Support\Facades\Queue;
-use Mockery;
 
 beforeEach(function () {
     Queue::fake();