[6.x] Support Glide 4 and Intervention Image 4

[joshuablum]

Laravel 13.20 added first party image processing (laravel/framework#59276), which requires intervention/image v4. Statamic uses Glide and our usage of league/glide ^3.0 pins intervention/image to ^3.9.1. Since you can't use two versions of a package at the same time, anyone on Laravel 13.20+ who would reach for the new Image API would get an error.

Laravel's change introducing the feature doesn't break any existing Statamic sites which is good. This only affects people who want to use the new feature.

The PR widens the constraint to league/glide: ^3.0 || ^4.0. Glide 4 migrated to Intervention Image v4, so allowing it is what allows to use Laravel Image API. This means nobody is forced to upgrade but requires a small version check/compatibility layer. The Glide API between v3 and v4 is unchanged for everything we use but Intervention requires some adjustments:

v3	v4
$manager->read()	decodeBinary()
$manager->create()	createImage()
$image->pickColor()	colorAt()
$image->blendTransparency()	fillTransparentAreas()
$image->encodeByExtension()	encodeUsingFileExtension()

orient(), crop(), width(), height(), fill() and DriverInterface::supports() are identical in both, so ImageValidator's logic is untouched.

Introducing a small Statamic\Imaging\Intervention class which can be removed when we eventually drop Glide v3 with Statamic 7(?).

This also fixes a latent break in GlideServiceProvider, which called $imageManager->driver(). v4 doesn't have that method but it's a public property instead. The validator's driver is now built directly.

Dependency note

If you are calling Intervention methods manually in app code or addon code, now that we are allowing intervention v4, technically your code could break as v4 would get installed where you're expecting v3.

If you're calling Intervention directly, you should have been explicitly requiring it. But it works without doing it. It's a common mistake - one we're resolving in this PR ourselves.

Add "intervention/image": "^3.9.1" to your composer.json if you need to remain on v3.