fix(player): persist queue panel visibility + drop dead loudness binding (#336)

* feat(player): persist queue panel visibility across restarts

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* chore(audio): drop unused resolved_loudness_gain_db binding

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src-tauri/src/audio.rs

@@ -4422,7 +4422,6 @@ pub fn audio_update_replay_gain(
             },
         )
     });
-    let resolved_loudness_gain_db = cache_loudness.or(loudness_gain_db);
     let effective_loudness_db = if norm_mode == 2 {
         match url_for_loudness.as_deref() {
             Some(_u) => loudness_gain_db_after_resolve(

src/store/playerStore.ts

@@ -3121,6 +3121,7 @@ export const usePlayerStore = create<PlayerState>()(
         currentTrack: state.currentTrack,
         queue: state.queue,
         queueIndex: state.queueIndex,
+        isQueueVisible: state.isQueueVisible,
         // currentTime is intentionally NOT persisted here.
         // handleAudioProgress fires every 100ms and each setState with a
         // persisted field triggers a full JSON serialisation of the queue to