feat(sandbox): rebuild sandbox with shell UI and expanded templates (#773)

packages/sandbox/templates/shared/react/use-source.ts

@@ -0,0 +1,9 @@
+import { useEffect, useState } from 'react';
+import { getInitialSource, onSourceChange } from '../sandbox-listener';
+import type { SourceId } from '../sources';
+
+export function useSource(audioOnly?: boolean): SourceId {
+  const [source, setSource] = useState(() => getInitialSource(audioOnly));
+  useEffect(() => onSourceChange(setSource), []);
+  return source;
+}