Add a typed platform package to decouple the frontend from Tauri (#539)

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

apps/yaak-client/hooks/usePlatformEvent.ts

@@ -0,0 +1,12 @@
+import { platform } from "@yaakapp-internal/platform";
+import { useEffect, useRef } from "react";
+
+/** Subscribe to a backend event for the lifetime of the component. */
+export function usePlatformEvent<T>(event: string, fn: (payload: T) => void) {
+  const handlerRef = useRef(fn);
+  useEffect(() => {
+    handlerRef.current = fn;
+  }, [fn]);
+
+  useEffect(() => platform.listen<T>(event, (payload) => handlerRef.current(payload)), [event]);
+}