Add basic screen sharing

src/app/components/VideoCallVideo.svelte

@@ -5,10 +5,11 @@
   type Props = {
     track: Track
     muted?: boolean
+    fit?: "cover" | "contain"
     class?: string
   }
 
-  const {track, muted = true, class: className = ""}: Props = $props()
+  const {track, muted = true, fit = "cover", class: className = ""}: Props = $props()
 
   let el = $state<HTMLVideoElement | undefined>()
 
@@ -23,5 +24,8 @@
   })
 </script>
 
-<video bind:this={el} class={cx("h-full w-full object-cover", className)} playsinline {muted}
-></video>
+<video
+  bind:this={el}
+  class={cx("h-full w-full", fit === "contain" ? "object-contain" : "object-cover", className)}
+  playsinline
+  {muted}></video>