feat: customizable queue toolbar with drag-and-drop reordering and visibility toggles (#534)

* Add drag-and-drop reordering and visibility toggles for queue toolbar

* docs(changelog): credit PR #534 (queue toolbar customization)

Adds the v1.46.0 CHANGELOG entry and a new bullet on kveld9's
contributors block in Settings → System.

---------

Co-authored-by: Psychotoxical <171614930+Psychotoxical@users.noreply.github.com>

src/store/queueToolbarStore.ts

@@ -0,0 +1,70 @@
+import { create } from 'zustand';
+import { persist } from 'zustand/middleware';
+
+export type QueueToolbarButtonId =
+  | 'shuffle'
+  | 'save'
+  | 'load'
+  | 'share'
+  | 'clear'
+  | 'separator'
+  | 'gapless'
+  | 'crossfade'
+  | 'infinite';
+
+export interface QueueToolbarButtonConfig {
+  id: QueueToolbarButtonId;
+  visible: boolean;
+}
+
+/**
+ * Default order and visibility for queue toolbar buttons.
+ * Matches the historical layout in QueuePanel.tsx.
+ */
+export const DEFAULT_QUEUE_TOOLBAR_BUTTONS: QueueToolbarButtonConfig[] = [
+  { id: 'shuffle',   visible: true },
+  { id: 'save',      visible: true },
+  { id: 'load',      visible: true },
+  { id: 'share',     visible: true },
+  { id: 'clear',     visible: true },
+  { id: 'separator', visible: true },
+  { id: 'gapless',   visible: true },
+  { id: 'crossfade', visible: true },
+  { id: 'infinite',  visible: true },
+];
+
+interface QueueToolbarStore {
+  buttons: QueueToolbarButtonConfig[];
+  setButtons: (buttons: QueueToolbarButtonConfig[]) => void;
+  toggleButton: (id: QueueToolbarButtonId) => void;
+  reset: () => void;
+}
+
+export const useQueueToolbarStore = create<QueueToolbarStore>()(
+  persist(
+    (set) => ({
+      buttons: DEFAULT_QUEUE_TOOLBAR_BUTTONS,
+
+      setButtons: (buttons) => set({ buttons }),
+
+      toggleButton: (id) => set((s) => ({
+        buttons: s.buttons.map(btn => btn.id === id ? { ...btn, visible: !btn.visible } : btn),
+      })),
+
+      reset: () => set({ buttons: DEFAULT_QUEUE_TOOLBAR_BUTTONS }),
+    }),
+    {
+      name: 'psysonic_queue_toolbar',
+      onRehydrateStorage: () => (state) => {
+        if (!state) return;
+        // Sanitize: remove null/corrupt entries
+        const knownIds = new Set(DEFAULT_QUEUE_TOOLBAR_BUTTONS.map(b => b.id));
+        const safe = (state.buttons ?? [])
+          .filter((b): b is QueueToolbarButtonConfig => b != null && typeof b.id === 'string' && knownIds.has(b.id as QueueToolbarButtonId));
+        const seen = new Set(safe.map(b => b.id));
+        const missing = DEFAULT_QUEUE_TOOLBAR_BUTTONS.filter(b => !seen.has(b.id));
+        state.buttons = missing.length > 0 ? [...safe, ...missing] : safe;
+      },
+    }
+  )
+);