Add basic screen sharing

src/app/components/VoiceWidget.svelte

@@ -8,6 +8,8 @@
   import MicrophoneOff from "@assets/icons/microphone-off.svg?dataurl"
   import Videocamera from "@assets/icons/videocamera.svg?dataurl"
   import VideocameraRecord from "@assets/icons/videocamera-record.svg?dataurl"
+  import ScreenShare from "@assets/icons/screen-share.svg?dataurl"
+  import Screencast from "@assets/icons/screencast.svg?dataurl"
   import PhoneRounded from "@assets/icons/phone-rounded.svg?dataurl"
   import PhoneCallingRounded from "@assets/icons/phone-calling-rounded.svg?dataurl"
   import CloseCircle from "@assets/icons/close-circle.svg?dataurl"
@@ -34,6 +36,7 @@
     leaveVoiceRoom,
     toggleMute,
     toggleCamera,
+    toggleScreenShare,
     cancelJoinVoiceRoom,
   } from "@app/voice"
 
@@ -122,6 +125,14 @@
           btn-ghost" onclick={openAudioSettings}>
           <Icon icon={Settings} size={4} />
         </Button>
+        <Button
+          data-tip={$currentVoiceSession.screenShareOn ? "Stop sharing" : "Share screen"}
+          class="center tooltip tooltip-top btn btn-sm btn-square {$currentVoiceSession.screenShareOn
+            ? 'btn-ghost'
+            : 'btn-error'}"
+          onclick={toggleScreenShare}>
+          <Icon icon={$currentVoiceSession.screenShareOn ? Screencast : ScreenShare} size={4} />
+        </Button>
         <Button
           data-tip="Leave room"
           class="center tooltip tooltip-top btn btn-sm btn-square btn-error"