feat(admin): rebuild release upload form with Livewire and CDN validation

Replace the server-rendered release upload form with a Livewire component,
introducing an interactive admin release form that supports dynamic episode
management, real‑time CDN path validation, and direct download file checks.

Key changes:
- New `AdminReleaseForm` Livewire component with dynamic episode fields,
  Tagify integration, and upload handling via Livewire's file uploads.
- Added `CdnPathValidator` service to verify download and stream paths across
  all configured mirrors, caching results and capturing file sizes.
- Extended `EpisodeService` and `GalleryService` to support array‑based data
  and temporary uploaded files from Livewire.
- Persist validated download sizes and store the validation timestamp on the
  `downloads` table via a new migration; also add a unique constraint on
  `hentais.slug` to prevent duplicates.
- Remove the old POST `/admin/release/upload` route and controller logic,
  along with the legacy `upload.js` script.
- Add comprehensive feature and unit tests covering the new component and the
  CDN validation service.

app/Services/GalleryService.php

@@ -6,9 +6,11 @@ use App\Models\Episode;
 use App\Models\Gallery;
 use App\Models\Hentai;
 use Illuminate\Http\Request;
+use Illuminate\Http\UploadedFile;
 use Illuminate\Support\Facades\Storage;
 use Intervention\Image\Encoders\WebpEncoder;
 use Intervention\Image\Laravel\Facades\Image;
+use Livewire\Features\SupportFileUploads\TemporaryUploadedFile;
 
 class GalleryService
 {
@@ -17,17 +19,26 @@ class GalleryService
         $galleryInputNumber = $override ? 1 : $episodeNumber;
 
         if ($request->hasFile('episodegallery'.$galleryInputNumber)) {
+            $this->saveGalleryFiles($hentai, $episode, $episodeNumber, $request->file('episodegallery'.$galleryInputNumber));
+        }
+    }
 
-            $this->deleteOldGallery($episode);
+    /**
+     * Save a gallery for the given episode from a list of uploaded files.
+     *
+     * @param  array<int, UploadedFile|TemporaryUploadedFile>  $files
+     */
+    public function saveGalleryFiles(Hentai $hentai, Episode $episode, int $episodeNumber, array $files): void
+    {
+        $this->deleteOldGallery($episode);
 
-            $this->createGalleryFolder($hentai);
+        $this->createGalleryFolder($hentai);
 
-            $counter = 0;
-            foreach ($request->file('episodegallery'.$galleryInputNumber) as $file) {
-                $gallery = $this->createGallery($hentai, $episode, $episodeNumber, $counter);
-                $this->saveGalleryImage($gallery, $file);
-                $counter += 1;
-            }
+        $counter = 0;
+        foreach ($files as $file) {
+            $gallery = $this->createGallery($hentai, $episode, $episodeNumber, $counter);
+            $this->saveGalleryImage($gallery, $file);
+            $counter += 1;
         }
     }
 
@@ -51,7 +62,7 @@ class GalleryService
         return $gallery;
     }
 
-    private function saveGalleryImage(Gallery $gallery, $sourceImage): void
+    private function saveGalleryImage(Gallery $gallery, UploadedFile|TemporaryUploadedFile $sourceImage): void
     {
         Image::read($sourceImage->getRealPath())
             ->cover(1920, 1080)