Refine shell status icons and window controls; add installer

shell/ferese-shell/assets/icons/status/volume-low.svg

@@ -1,5 +1,7 @@
-<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round">
-  <path d="M3 9h4l5-4v14l-5-4H3Z"/>
-  <path d="M15.2 8.5a5 5 0 0 1 0 7" opacity="0.24"/>
-  <path d="M18.4 5.5a9.2 9.2 0 0 1 0 13" opacity="0.24"/>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 60 60" role="img" aria-label="Audio">
+<g transform="translate(3 0)">
+<path d="M27.5,12.5 L15,22.5 L5,22.5 L5,37.5 L15,37.5 L27.5,47.5 Z" fill="currentColor"/>
+<path d="M34,22 Q40,30 34,38" fill="none" stroke="currentColor" stroke-width="4" stroke-linecap="round"/>
+<path d="M40,15 Q50,30 40,45" fill="none" opacity="0.18" stroke="#3d7be6" stroke-width="4" stroke-linecap="round"/>
+</g>
 </svg>