add video to livekit calls

src/lib/components/PageContent.svelte

@@ -5,14 +5,19 @@
   interface Props {
     element?: Element
     children?: Snippet
+    /** Desktop voice: chat occupies the right half in split view. */
+    contentFrame?: "default" | "split-right"
     [key: string]: any
   }
 
-  let {children, element = $bindable(), ...props}: Props = $props()
+  let {children, element = $bindable(), contentFrame = "default", ...props}: Props = $props()
 
-  const className = cx(
-    props.class,
-    "scroll-container cw cb ct fixed z-feature overflow-y-auto overflow-x-hidden",
+  const className = $derived(
+    cx(
+      props.class,
+      "scroll-container cb ct fixed z-feature overflow-y-auto overflow-x-hidden",
+      contentFrame === "split-right" ? "cw-split-chat" : "cw",
+    ),
   )
 </script>