fix: support parameterless policy methods for guest access

[binaryk]

Problem

Laravel's Gate denies guest access to a policy method unless that method declares a nullable $user as its first parameter. Gate::policyAllowsGuests() inspects the method signature and returns false when the parameter is absent, so even a policy like:

public function allowRestify(): bool
{
    return true;
}

would return a 403 for unauthenticated requests — despite explicitly returning true.

Fix

AuthorizableModels now has a checkPolicyMethod() helper that uses ReflectionMethod to detect when a policy method has zero parameters. In that case it calls the method directly, bypassing Gate's guest-check logic entirely. When the method does have parameters the existing Gate::check() path is used unchanged.

The helper is used in the four existing call sites: authorizedToUseRepository, authorizedToStore, authorizedToStoreBulk, and authorizedTo.

Tests

tests/Feature/ParameterlessPolicyTest.php covers three scenarios using a ParameterlessAllowPolicy whose allowRestify() has no parameters:

• Unauthenticated request is allowed when the parameterless policy returns true (the key regression case — previously returned 403)
• Unauthenticated request is denied when the parameterless policy returns false
• Authenticated request is allowed when the parameterless policy returns true

Test plan

• ./vendor/bin/phpunit tests/Feature/ParameterlessPolicyTest.php — 3 tests pass
• ./vendor/bin/phpunit tests/Feature/AuthorizableModelsTest.php — 4 existing tests still pass
• Verify that a policy with a parameterless allowRestify(): bool { return true; } no longer returns 403 for guest requests