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/ServerQueryScopeTest.php

@@ -3,7 +3,6 @@
 use App\Enums\ProxyTypes;
 use App\Models\Server;
 use Illuminate\Database\Eloquent\Builder;
-use Mockery;
 
 it('filters servers by proxy type using whereProxyType scope', function () {
     // Mock the Builder