fix(jellyfin-scan): reduce jellyfin API calls during recently added scan (#2205)

* fix(jellyfin scanner): reduce jellyfin API calls during recently added scan

Significantly reduce number of API calls, addressing CPU spikes on Jellyfin 10.10+ servers.- Move
getSeasons() call outside the seasons loop (N calls to 1)- Request MediaSources via getEpisodes()
field parameter instead of  individual getItemData() calls per episode (N calls to 1 per season)
Performance improvements (tested on library with 12 TV shows):- Scan duration: 43.7s to 9.1s - Peak
CPU: 277% to 115% - CPU spike duration: 36s to 2s Functionality is unchanged, all availability
statuses identicalbefore and after.

* fix: add getEpisodes overloads to remove unsafe type assertion

* refactor(jellyfin): use generics instead of overloads

---------

Co-authored-by: patrick-acland <patrick.acland@kraken.tech>

server/api/jellyfin.ts

@@ -112,6 +112,10 @@ export interface JellyfinLibraryItemExtended extends JellyfinLibraryItem {
   DateCreated?: string;
 }
 
+type EpisodeReturn<T> = T extends { includeMediaInfo: true }
+  ? JellyfinLibraryItemExtended[]
+  : JellyfinLibraryItem[];
+
 export interface JellyfinItemsReponse {
   Items: JellyfinLibraryItemExtended[];
   TotalRecordCount: number;
@@ -415,13 +419,22 @@ class JellyfinAPI extends ExternalAPI {
     }
   }
 
-  public async getEpisodes(
+  public async getEpisodes<
+    T extends { includeMediaInfo?: boolean } | undefined = undefined
+  >(
     seriesID: string,
-    seasonID: string
-  ): Promise<JellyfinLibraryItem[]> {
+    seasonID: string,
+    options?: T
+  ): Promise<EpisodeReturn<T>> {
     try {
       const episodeResponse = await this.get<any>(
-        `/Shows/${seriesID}/Episodes?seasonId=${seasonID}`
+        `/Shows/${seriesID}/Episodes`,
+        {
+          params: {
+            seasonId: seasonID,
+            ...(options?.includeMediaInfo && { fields: 'MediaSources' }),
+          },
+        }
       );
 
       return episodeResponse.Items.filter(