feat(Composite): Enhance root and child rendering with error differentiation

- Adjusted Composite to conditionally check for both direct root and child rendering.
- Differentiated error states: omitting an error when `component` prop is absent but showing an error when it's undefined.
- Fixed rendering of @app in the messages stream.

src/lib/components/Messages.svelte

@@ -40,7 +40,7 @@
 		<!-- Render Composite Component -->
 		{#if message.composite}
 			<div class="overflow-y-auto max-h-80vh">
-				<Composite componentsData={message.composite} />
+				<Composite composite={message.composite} />
 			</div>
 		{/if}
 	{/each}