Refine shell status icons and window controls; add installer

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

@@ -1,4 +1,8 @@
-<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="M10.3 4.8A5.5 5.5 0 0 1 17.5 10v3M6.7 8.6a5.5 5.5 0 0 0-.2 1.4v4.5L5 17h10M10 20a2.3 2.3 0 0 0 4 0"/>
-  <path d="M4 4l16 16"/>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 60 60" role="img" aria-label="Notification off">
+<g transform="translate(0 -2)">
+<path d="M30,10 A16,16 0 0,1 46,26 L46,38 L14,38 L14,26 A16,16 0 0,1 30,10 Z" fill="currentColor" opacity="0.5"/>
+<rect x="10" y="38" width="40" height="5" rx="2" fill="currentColor" opacity="0.5"/>
+<circle cx="30" cy="50" r="4" fill="currentColor" opacity="0.5"/>
+<path d="M8,8 L52,56" fill="none" stroke="currentColor" stroke-width="5" stroke-linecap="round"/>
+</g>
 </svg>