Adopt Laravel's Image facade for media processing, upgrade Intervention to v4

Laravel 13's Image facade wraps Intervention Image v4 internally, so
switching our upload width probe and resize job/command to it required
bumping intervention/image ^3 -> ^4 (and its intervention/gif ^5
dependency). Removes our own ImageManager container binding and
config/image.php in favour of Laravel's built-in driver resolution.

Also fixes a latent filename mismatch in ProcessMediaJobTest that Pint's
stricter typing on the new Image API turned into a hard TypeError, and
tidies config/flare.php to use imported class names instead of FQCNs.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018Sorsgn85nw7uQyRMNvzyD

app/Http/Controllers/MicropubMediaController.php

@@ -13,9 +13,10 @@ use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
 use Illuminate\Http\Response;
 use Illuminate\Http\UploadedFile;
+use Illuminate\Image\ImageException;
 use Illuminate\Support\Carbon;
+use Illuminate\Support\Facades\Image;
 use Illuminate\Support\Facades\Storage;
-use Intervention\Image\ImageManager;
 use Ramsey\Uuid\Uuid;
 
 class MicropubMediaController extends Controller
@@ -111,12 +112,9 @@ class MicropubMediaController extends Controller
 
         $filename = Storage::disk('local')->putFile('media', $file);
 
-        /** @var ImageManager $manager */
-        $manager = resolve(ImageManager::class);
         try {
-            $image = $manager->read($request->file('file'));
-            $width = $image->width();
-        } catch (Exception) {
+            $width = Image::fromUpload($request->file('file'))->width();
+        } catch (ImageException) {
             // not an image
             $width = null;
         }