- Classify .gif as EAssetType.Video via MimeTypes (moved image/gif to the Video registry)
- Add MediaRepository.GetConvertedData, served by the existing media/{id} endpoint
when a converted file exists on disk (with a fallback + warning log if missing)
- Expose the converted MIME type on AssetPreviewDto/AlbumAssetPreviewDto
so the frontend can detect video assets from a single MimeType field