Fix: eliminate reload-only hydration mismatches on home

Make HomePage a server component and mount ActivityFeed via a client-only wrapper to avoid Suspense/dynamic boundary differences between SSR and hydration.

app/_ui/ActivityFeedClient.tsx

@@ -0,0 +1,31 @@
+"use client";
+
+import React, { useEffect, useState } from "react";
+
+type ActivityFeedComponent = React.ComponentType<Record<string, never>>;
+
+export default function ActivityFeedClient() {
+  const [Comp, setComp] = useState<ActivityFeedComponent | null>(null);
+
+  useEffect(() => {
+    let cancelled = false;
+    (async () => {
+      try {
+        const mod = await import("../components/ActivityFeed");
+        const C = (mod as unknown as { default?: ActivityFeedComponent }).default;
+        if (!cancelled && typeof C === "function") {
+          setComp(() => C);
+        }
+      } catch {
+        // ignore
+      }
+    })();
+    return () => {
+      cancelled = true;
+    };
+  }, []);
+
+  if (!Comp) return null;
+  return <Comp />;
+}
+