feat(qbz-slint): Queue+Lyrics stacking, NowPlayingBar polish, shell fill fix

NowPlayingBar / SongCard:
- Audio stamp homologated New<->Classic + vertically centred (alignment:center
  on the stamp column; New had a binding-loop card height, now explicit).
- Dot-LED output indicators (circle-dot/circle) in both modes; render-target
  badge moved into the LED row when a peer/cast device owns playback.
- Right-cluster buttons made square (32x32); context glyph -> disc-album,
  flush-left; classic stamp right margin; quality tooltip = the quality text;
  heart tooltip = Add to library; Qobuz Connect tooltip always shows On/Off.

Qobuz Connect:
- Clear the session topology on disconnect so a late event cannot resurrect
  the golden render badge (badge-persists-after-disconnect fix).

Queue / Lyrics right panel:
- Queue and Lyrics can both be open at once, stacked vertically in one column
  (independent queue-open/lyrics-open flags replace the exclusive right-panel
  int); each closable from its bar button and its own X.
- Panel width 280; compact rows (zebra), now-playing card homologated with a
  row, flexible footer search, Lyrics title sized like the Queue tabs.

Shell layout:
- Pin AppShell to the window and size the content area arithmetically
  (window - header - player-bar - padding). A Slint VerticalLayout ignores an
  explicit height and does not auto-fill its parent Rectangle, so the content
  row collapsed once the right panels became conditionally mounted; a Rectangle
  takes the explicit height and it cascades up. Bar height references the single
  Layout.player-bar-height source (note left for the future Small/Large bars).

cc

crates/qbz-slint/src/qconnect_service.rs

@@ -448,6 +448,14 @@ impl SlintQconnectService {
             {
                 let mut state = runtime.sync_state.lock().await;
                 state.watchdog_generation = state.watchdog_generation.wrapping_add(1);
+                // Clear the session topology + per-renderer cache so that any
+                // event still in flight when the loop aborts cannot recompute
+                // `is_peer_renderer_active() == true` and resurrect the golden
+                // render badge AFTER we clear is-remote/cast-target below
+                // (tokio `abort()` is not instantaneous; the sink can run one
+                // more `refresh_now_playing_remote_state` from a stale session).
+                state.session = QconnectSessionState::default();
+                state.session_renderer_states.clear();
             }
             if let Err(err) = runtime.app.disconnect().await {
                 let mut guard = self.inner.lock().await;