Refine shell status icons and window controls; add installer

shell/ferese-shell/assets/icons/status/bluetooth-off.svg

@@ -1,4 +1,4 @@
-<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="M12 3l5.5 4.5-3.2 2.9M12 3v5M7.5 16.5l2.7-2.4M12 16v5l3.5-2.9"/>
-  <path d="M4 4l16 16"/>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 60 60" role="img" aria-label="Bluetooth off">
+<g transform="translate(-6 -4)"><path d="M30,10 L30,58 M30,10 L42,22 L30,34 L42,46 L30,58" fill="none" stroke="currentColor" stroke-width="5" stroke-linecap="round" stroke-linejoin="round" opacity="0.5"/></g>
+<path d="M8,8 L52,52" fill="none" stroke="currentColor" stroke-width="5" stroke-linecap="round"/>
 </svg>