feat: Waveform seekbar, MilkDrop visualizer, EQ bars, in-app browser, and UX improvements (v1.3.0)

- PlayerBar redesigned: canvas waveform seekbar (500 bars, blue→mauve gradient + glow) replaces thin slider; new flex layout; queue toggle moved to content header (consistent with sidebar pattern)
- MilkDrop visualizer in Ambient Stage via Butterchurn; hidden audio analysis, preset shuffle, smooth blend transitions
- Tracklist: animated EQ bars for playing track, play icon when paused, align-items: center fix
- Artist pages: Last.fm + Wikipedia open in native Tauri WebviewWindow (in-app browser)
- Hero/Discover deduplication: single fetch of 20 random albums split between sections
- Update checker: runs every 10 minutes during runtime; version shown without v-prefix
- Settings version: now read from package.json instead of hardcoded
- Help page: new Random Mix section, updated Playback + Library sections, improved accordion styling
- Bump version to 1.3.0

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

src-tauri/capabilities/default.json

@@ -27,6 +27,8 @@
     "core:window:allow-hide",
     "core:window:allow-show",
     "core:window:allow-set-fullscreen",
-    "core:window:allow-is-fullscreen"
+    "core:window:allow-is-fullscreen",
+    "core:window:allow-create",
+    "core:webview:allow-create-webview-window"
   ]
 }