chore: Improve desktop integration and AppImage metadata for release

- Add Comment field to all .desktop files for app launcher descriptions
- Change category from Music to AudioVideo for better categorization
- Add Keywords for improved searchability (audiophile, hifi, streaming)
- Enhance metainfo.xml with detailed feature list and links
- Configure AppImage bundle settings in tauri.conf.json
- Update workflows to generate improved .desktop files

AppImage now includes embedded icon via Tauri icon configuration.
App will now appear in Multimedia category with proper description in all Linux app launchers.

packaging/flatpak/com.blitzfc.qbz.metainfo.xml

@@ -2,17 +2,48 @@
 <component type="desktop-application">
   <id>com.blitzfc.qbz</id>
   <name>QBZ</name>
-  <summary>Native Qobuz client for Linux</summary>
+  <summary>Native Qobuz client with hi-res audio support</summary>
   <description>
-    <p>QBZ is a native Qobuz streaming client for Linux designed for audiophiles.</p>
-    <p>It focuses on bit-perfect playback without browser sample-rate limits.</p>
+    <p>
+      QBZ is a native Qobuz streaming client for Linux designed for audiophiles who demand the highest audio quality.
+    </p>
+    <p>Features:</p>
+    <ul>
+      <li>Bit-perfect playback up to 24-bit/192kHz without browser limitations</li>
+      <li>Native hi-res audio support with ALSA, PulseAudio, and PipeWire backends</li>
+      <li>Advanced audio routing and exclusive mode for DACs</li>
+      <li>Beautiful, responsive interface optimized for music discovery</li>
+      <li>Offline playlist support for on-the-go listening</li>
+      <li>Radio Engine for infinite music discovery based on your favorite artists</li>
+      <li>Smart recommendations powered by local machine learning</li>
+      <li>MPRIS integration for desktop media controls</li>
+      <li>Last.fm scrobbling support</li>
+    </ul>
+    <p>
+      Built with Tauri and Rust for optimal performance and reliability.
+    </p>
   </description>
-  <developer_name>QBZ</developer_name>
+  <developer_name>QBZ Contributors</developer_name>
+  <url type="homepage">https://github.com/vicrodh/qbz</url>
+  <url type="bugtracker">https://github.com/vicrodh/qbz/issues</url>
   <metadata_license>CC0-1.0</metadata_license>
   <project_license>MIT</project_license>
   <categories>
+    <category>AudioVideo</category>
     <category>Audio</category>
     <category>Music</category>
+    <category>Player</category>
   </categories>
+  <keywords>
+    <keyword>music</keyword>
+    <keyword>audio</keyword>
+    <keyword>qobuz</keyword>
+    <keyword>hifi</keyword>
+    <keyword>streaming</keyword>
+    <keyword>audiophile</keyword>
+  </keywords>
   <launchable type="desktop-id">com.blitzfc.qbz.desktop</launchable>
+  <provides>
+    <binary>qbz</binary>
+  </provides>
 </component>