feat(mini-player): persistent geometry, queue DnD + context menu, overlay scrollbar, live theme sync

This iteration fills in the pieces that make the mini player usable as a
daily standalone window:

- Window position persists to <app_config_dir>/mini_player_pos.json on
  every WindowEvent::Moved (throttled 250 ms); first launch lands in the
  bottom-right of the main window's monitor.
- Queue keeps a 260 px floor when expanded (~2 visible rows). The
  user-resized expanded height is restored on next toggle via
  localStorage so reopening doesn't snap back to the default 440 px.
- set_mini_player_always_on_top(true) now forces a false-then-true cycle
  so the WM re-evaluates the layer after a hide/show; the frontend also
  re-asserts the pin state on mount and on window focus, so the user no
  longer has to click the pin button twice for it to stick.
- Native scrollbar in the queue is hidden in favour of a JS-driven
  overlay thumb so items use the full width of the queue area.
- PsyDnD reorder works inside the mini queue: drag emits 'mini:reorder',
  the bridge calls reorderQueue on the source-of-truth store in main.
- Localized queue-item context menu (MiniContextMenu) with Play now /
  Remove from queue / Open album / Go to artist / Favorite / Song info.
  Cross-window actions forward to main via new bridge events
  (mini:reorder, mini:remove, mini:navigate, mini:song-info); a
  psy:navigate CustomEvent picked up by AppShell handles routing.
- Theme, font and language changes in main propagate live to the mini
  via a 'storage' event listener that re-hydrates the persisted Zustand
  stores and calls i18n.changeLanguage.

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

src/App.tsx

@@ -146,6 +146,17 @@ function AppShell() {
   const offlineAlbums = useOfflineStore(s => s.albums);
   const hasOfflineContent = Object.values(offlineAlbums).some(a => a.serverId === serverId);
 
+  // Mini player → main: route requests dispatched as `psy:navigate`
+  // CustomEvents from the bridge land here so React Router can take over.
+  useEffect(() => {
+    const onPsyNavigate = (e: Event) => {
+      const detail = (e as CustomEvent).detail;
+      if (detail?.to) navigate(detail.to);
+    };
+    window.addEventListener('psy:navigate', onPsyNavigate);
+    return () => window.removeEventListener('psy:navigate', onPsyNavigate);
+  }, [navigate]);
+
   // Sync custom titlebar preference with native decorations on Linux
   // On tiling WMs decorations are always off (no native title bar to replace).
   useEffect(() => {
@@ -961,8 +972,32 @@ export default function App() {
     return initMiniPlayerBridgeOnMain();
   }, [isMiniWindow]);
 
+  // Mini window only: re-hydrate persisted appearance stores when the main
+  // window writes new values. Both webviews share localStorage (same origin),
+  // so the `storage` event fires here whenever main mutates a key — but
+  // Zustand persist only reads localStorage on initial load, hence the
+  // explicit rehydrate.
+  useEffect(() => {
+    if (!isMiniWindow) return;
+    const onStorage = (e: StorageEvent) => {
+      if (!e.key) return;
+      if (e.key === 'psysonic_theme') useThemeStore.persist.rehydrate();
+      else if (e.key === 'psysonic_font') useFontStore.persist.rehydrate();
+      else if (e.key === 'psysonic_language' && e.newValue) {
+        import('./i18n').then(m => m.default.changeLanguage(e.newValue!));
+      }
+    };
+    window.addEventListener('storage', onStorage);
+    return () => window.removeEventListener('storage', onStorage);
+  }, [isMiniWindow]);
+
   if (isMiniWindow) {
-    return <MiniPlayer />;
+    return (
+      <DragDropProvider>
+        <MiniPlayer />
+        <TooltipPortal />
+      </DragDropProvider>
+    );
   }
 
   // UI scaling is scoped to .main-content via an inner wrapper (see <main>