feat: initial qobuz-qt source

Lightweight Qt6 desktop client for Qobuz with a Rust audio backend
(Symphonia/CPAL via staticlib FFI). Mirrors the spotify-qt layout:
toolbar with playback controls, library/context docks on the left,
tabbed search side panel on the right, queue panel, now-playing dock.

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

res/icons/document-properties.svg

@@ -0,0 +1,14 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 22 22">
+  <defs id="defs3051">
+    <style type="text/css" id="current-color-scheme">
+      .ColorScheme-Text {
+        color:#eff0f1;
+      }
+      </style>
+  </defs>
+ <path 
+     style="fill:currentColor;fill-opacity:1;stroke:none" 
+	 d="m3 3v16h1 15v-1-15h-1-14-1m1 4h14v11h-14v-11m1 1v9h5v-9h-5m6 1v1h6v-1h-6m0 3v1h4v-1h-4m0 3v1h2v-1h-2"
+	 class="ColorScheme-Text"
+     />
+</svg>