fix: restore audio refactor + features lost in #419 squash-merge (#429)

The squash-merge of PR #419 was performed against an outdated PR base
that predated several main-side refactors and features. The resulting
squash inadvertently re-introduced files that had already been removed
(`src-tauri/src/audio.rs` monolith, `app-icon.png`) and reverted main's
content for ~20 files (`src-tauri/src/lib.rs` decompose, `src/App.tsx`
animation-pause, `src/components/AlbumRow.tsx` headerExtra, etc).

This commit:

* Restores all collateral-damage files to their pre-#419 main state
  (5662dafe), including the audio module split, lib decompose,
  Cargo.toml `windows` dep, animation-pause-on-blur logic, and
  `reducedAnimations` toggle plumbing in WaveformSeek/Settings.
* Keeps the genuine #419 work intact: tri-state duration toggle,
  position counter, persistent Now Playing collapse, animated EQ
  indicator (in QueuePanel.tsx, 8 locales, authStore, components.css).
* Merges authStore.ts so both `reducedAnimations` (from #426) and
  `queueNowPlayingCollapsed` (from #419) coexist.
* Adds the `.eq-bars.paused` CSS rule manually since components.css
  needed a 5662dafe base + the single #419 addition.
* Fixes a latent type error in OverlayScrollArea.tsx (`useRef<T>(null)`
  is `RefObject<T>` / read-only under current `@types/react`; widened to
  `useRef<T | null>(null)` so the existing `wrapRef.current = el`
  assignment compiles).

Verified locally with `cargo check` and `npm run build` — both green.

src/pages/Statistics.tsx

@@ -1,4 +1,5 @@
 import React, { useEffect, useState } from 'react';
+import { Share2 } from 'lucide-react';
 import {
   fetchStatisticsFormatSample,
   fetchStatisticsLibraryAggregates,
@@ -9,6 +10,7 @@ import {
 } from '../api/subsonic';
 import { formatHumanHoursMinutes } from '../utils/formatHumanDuration';
 import AlbumRow from '../components/AlbumRow';
+import StatsExportModal from '../components/StatsExportModal';
 import { useTranslation } from 'react-i18next';
 import { useAuthStore } from '../store/authStore';
 import { useNavigate } from 'react-router-dom';
@@ -51,6 +53,8 @@ export default function Statistics() {
   const [formatData, setFormatData] = useState<{ format: string; count: number }[] | null>(null);
   const [formatSampleSize, setFormatSampleSize] = useState(0);
 
+  const [exportOpen, setExportOpen] = useState(false);
+
   const [lfmPeriod, setLfmPeriod] = useState<LastfmPeriod>('1month');
   const [lfmTopArtists, setLfmTopArtists] = useState<LastfmTopArtist[]>([]);
   const [lfmTopAlbums, setLfmTopAlbums] = useState<LastfmTopAlbum[]>([]);
@@ -270,6 +274,17 @@ export default function Statistics() {
             albums={frequent}
             onLoadMore={() => loadMore('frequent', frequent, setFrequent)}
             moreText={t('statistics.loadMore')}
+            headerExtra={frequent.length >= 9 ? (
+              <button
+                type="button"
+                className="nav-btn"
+                onClick={() => setExportOpen(true)}
+                data-tooltip={t('statistics.exportTitle')}
+                aria-label={t('statistics.exportTitle')}
+              >
+                <Share2 size={18} />
+              </button>
+            ) : undefined}
           />
 
           <AlbumRow
@@ -384,6 +399,11 @@ export default function Statistics() {
 
         </div>
       )}
+      <StatsExportModal
+        open={exportOpen}
+        albums={frequent}
+        onClose={() => setExportOpen(false)}
+      />
     </div>
   );
 }