feat(server): hls with real-time transcoding (#28230)

* hls implementation

* fix stale state after ffmpeg exit

server/src/enum.ts

@@ -453,11 +453,7 @@ export enum VideoCodec {
 
 export const VideoCodecSchema = z.enum(VideoCodec).describe('Target video codec').meta({ id: 'VideoCodec' });
 
-export enum VideoSegmentCodec {
-  Av1 = 'av1',
-  Hevc = 'hevc',
-  H264 = 'h264',
-}
+export type VideoSegmentCodec = VideoCodec.Av1 | VideoCodec.Hevc | VideoCodec.H264;
 
 export enum AudioCodec {
   Mp3 = 'mp3',
@@ -827,6 +823,8 @@ export enum JobName {
   LibrarySyncFiles = 'LibrarySyncFiles',
   LibraryScanQueueAll = 'LibraryScanQueueAll',
 
+  HlsSessionCleanup = 'HlsSessionCleanup',
+
   MemoryCleanup = 'MemoryCleanup',
   MemoryGenerate = 'MemoryGenerate',
 
@@ -920,6 +918,7 @@ export enum DatabaseLock {
   MaintenanceOperation = 621,
   MemoryCreation = 777,
   VersionCheck = 800,
+  HlsSessionCleanup = 850,
 }
 
 export enum MaintenanceAction {