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.

app/Models/Project.php

@@ -4,6 +4,7 @@ namespace App\Models;
 
 use App\Traits\ClearsGlobalSearchCache;
 use App\Traits\HasSafeStringAttribute;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
 use OpenApi\Attributes as OA;
 use Visus\Cuid2\Cuid2;
 
@@ -20,6 +21,7 @@ use Visus\Cuid2\Cuid2;
 class Project extends BaseModel
 {
     use ClearsGlobalSearchCache;
+    use HasFactory;
     use HasSafeStringAttribute;
 
     protected $guarded = [];