chore: init monorepo snapshot

wolai-frontend/src/hooks/use-backend-health.ts

@@ -0,0 +1,40 @@
+import { useEffect, useState } from "react";
+
+type Status = "idle" | "ok" | "error";
+
+export function useBackendHealth() {
+  const [status, setStatus] = useState<Status>(() => {
+    if (!process.env.NEXT_PUBLIC_BACKEND_URL) {
+      return "error";
+    }
+    return "idle";
+  });
+
+  useEffect(() => {
+    let destroyed = false;
+    const url = process.env.NEXT_PUBLIC_BACKEND_URL;
+    if (!url) {
+      return;
+    }
+    const controller = new AbortController();
+    const check = async () => {
+      try {
+        const response = await fetch(`${url}/health`, { signal: controller.signal });
+        if (!destroyed) {
+          setStatus(response.ok ? "ok" : "error");
+        }
+      } catch {
+        if (!destroyed) {
+          setStatus("error");
+        }
+      }
+    };
+    check();
+    return () => {
+      destroyed = true;
+      controller.abort();
+    };
+  }, []);
+
+  return status;
+}