feat(sp6): Inbox page + useInboxLanes hook

src/hooks/useInboxLanes.ts

@@ -0,0 +1,41 @@
+import { useCallback, useEffect, useRef, useState } from "react";
+import { fetchInboxLanes, type InboxLanes } from "@/lib/inbox-api";
+
+/** Default poll interval. Tail-integration (T19) will replace this. */
+const POLL_INTERVAL_MS = 5_000;
+
+export function useInboxLanes() {
+  const [lanes, setLanes] = useState<InboxLanes>({
+    rejected: [],
+    candidates: [],
+    unmatched: [],
+    done_today: [],
+  });
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState<Error | null>(null);
+  const pollRef = useRef<ReturnType<typeof setInterval> | null>(null);
+
+  const refetch = useCallback(async () => {
+    try {
+      const next = await fetchInboxLanes();
+      setLanes(next);
+      setError(null);
+    } catch (e) {
+      setError(e as Error);
+    } finally {
+      setLoading(false);
+    }
+  }, []);
+
+  useEffect(() => {
+    void refetch();
+    pollRef.current = setInterval(() => {
+      void refetch();
+    }, POLL_INTERVAL_MS);
+    return () => {
+      if (pollRef.current) clearInterval(pollRef.current);
+    };
+  }, [refetch]);
+
+  return { lanes, loading, error, refetch };
+}