fix(phpstan): use covariant Model in Scope apply signatures for laravel 13 [3.x]

[ManukMinasyan]

Summary

• Update @param Builder<Model> to @param Builder<covariant Model> on apply() methods of all 4 scope classes
• Add the matching @param docblock to CustomFieldsActivableScope::apply() (PHPStan flagged it directly despite #[Override])

Why

Laravel 13's Illuminate\Database\Eloquent\Scope::apply() declares Builder<covariant Model>. PHPStan failed in the L13.* - prefer-stable matrix because the invariant Builder<Model> in the implementing classes was incompatible with the covariant parent signature.

Test plan

• vendor/bin/phpstan analyse --memory-limit=2G → No errors (lockfile on laravel/framework v13.6.0)
• vendor/bin/pint --test → pass
• vendor/bin/rector --dry-run → OK
• CI green on L12.* - prefer-stable and L13.* - prefer-stable matrices

[Copilot]

Pull request overview

Updates Eloquent global-scope apply() phpdoc generics to match Laravel 13’s Illuminate\Database\Eloquent\Scope::apply() signature (Builder<covariant Model>), resolving PHPStan/Larastan variance incompatibilities in the Laravel 13 matrix.

Changes:

• Switch @param Builder<Model> to @param Builder<covariant Model> on apply() across the scope implementations.
• Add the missing matching @param docblock to CustomFieldsActivableScope::apply() so PHPStan recognizes the covariant signature there as well.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
src/Models/Scopes/TenantScope.php	Updates apply() builder generic to Builder<covariant Model> for Laravel 13 compatibility.
src/Models/Scopes/SortOrderScope.php	Updates apply() builder generic to Builder<covariant Model> for Laravel 13 compatibility.
src/Models/Scopes/CustomFieldsActivableScope.php	Adds apply() builder generic docblock (Builder<covariant Model>) to satisfy PHPStan on override.
src/Models/Scopes/ActivableScope.php	Updates apply() builder generic to Builder<covariant Model> to match Laravel 13’s covariant signature.