feat: Rust audio engine, genre mix, queue shuffle, and UX improvements (v1.2.0)

### Audio Engine
- Replace Howler.js with native Rust/rodio backend (src-tauri/src/audio.rs)
- audio_play/pause/resume/stop/seek/set_volume Tauri commands
- Generation counter cancels stale in-flight downloads on skip
- Wall-clock position tracking; audio:ended after 2 ticks near end

### Playback Persistence
- Persist currentTrack, queue, queueIndex, currentTime to localStorage
- Cold-start resume: play + seek to saved position on app restart
- Position priority: server queue > localStorage

### Random Mix
- Genre blacklist: excludeAudiobooks toggle + custom chip-based blacklist
- Clickable genre chips in tracklist to blacklist on the fly
- Super Genre Mix: 9 genres, progressive rendering, Load 10 more
- Promise.allSettled + 45s timeout for large Metal/Rock libraries
- Two-column filter panel at top of page

### Queue & UI
- Shuffle button in queue header (Fisher-Yates, keeps current track at 0)
- LiveSearch arrow key / Enter / Escape keyboard navigation
- Multi-line tooltip support (data-tooltip-wrap attribute)
- Update link uses Tauri shell open() to launch system browser
- Sidebar min-width 180px → 200px (fixes Psysonic title clipping)
- Tooltip z-index fix: main-content z-index:1 over queue panel

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/Sidebar.tsx

@@ -1,4 +1,5 @@
 import React, { useEffect, useState } from 'react';
+import { open } from '@tauri-apps/plugin-shell';
 import { version as appVersion } from '../../package.json';
 import { NavLink } from 'react-router-dom';
 import { useTranslation } from 'react-i18next';
@@ -49,14 +50,12 @@ function UpdateToast({ isCollapsed, latestVersion }: { isCollapsed: boolean; lat
         <span className="update-toast-label">{t('sidebar.updateAvailable')}</span>
       </div>
       <div className="update-toast-version">{t('sidebar.updateReady', { version: latestVersion })}</div>
-      <a
+      <button
         className="update-toast-link"
-        href="https://github.com/Psychotoxical/psysonic/releases"
-        target="_blank"
-        rel="noopener noreferrer"
+        onClick={() => open('https://github.com/Psychotoxical/psysonic/releases')}
       >
         {t('sidebar.updateLink')}
-      </a>
+      </button>
     </div>
   );
 }