[enhancement]: better version checks for lyrics, Navidrome (#529)

- Actually make serverfeatures partial
- Navidrome: only set multiple structured lyrics if extension exists
- Navidrome/Subsonic: minor type checking of OS extension (Navidrome implementation detail)
- Jellyfin: add separate knob for lyrics. Note, this should also probably be behind some version check...

src/renderer/api/utils.ts

@@ -45,5 +45,5 @@ export const hasFeature = (server: ServerListItem | null, feature: ServerFeature
         return false;
     }
 
-    return server.features[feature];
+    return server.features[feature] ?? false;
 };