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.
w33b