fix(jellyfin): show overlay, inject plugin, and fix stats title on playb

- Show visible overlay automatically during Jellyfin playback so subtitleStyle applies
- Inject bundled mpv plugin on auto-launch so keybindings work without overlay focus
- Group Jellyfin playback stats under item metadata (jellyfin://host/item/id) instead of stream URLs so episodes merge with matching local titles
- Mark ffsubsync unavailable in subsync modal for remote media paths
- Drain queued second-instance commands even when onReady throws

docs-site/mining-workflow.md

@@ -164,6 +164,8 @@ If your subtitle file is out of sync with the audio, SubMiner can resynchronize
 3. For alass, select a reference subtitle track from the video.
 4. SubMiner runs the sync and reloads the corrected subtitle.
 
+For remote streams, including Jellyfin playback, the modal only offers alass. Jellyfin subtitle URLs are cached as temporary subtitle files so alass can read them, but the video stream is not downloaded. ffsubsync needs direct access to the local media file and is unavailable for stream URLs.
+
 Install the sync tools separately — see [Troubleshooting](/troubleshooting#subtitle-sync-subsync) if the tools are not found.
 
 ## Texthooker