refactor: add explicit any types and improve readability in group state handling

- Updated `setProject` function in `page.tsx` to include explicit `(prev: any)` and `(group: any)` type annotations for better readability.
- Added `"use client";` directive to `notifications.tsx` for React server-client compatibility.
- Improved structural consistency and clarity in group and person state updates.

frontend/components/notifications.tsx

@@ -1,3 +1,5 @@
+"use client";
+
 import { useEffect, useState } from "react";
 import { useSocket } from "@/lib/socket-context";
 import { toast } from "sonner";
@@ -60,4 +62,4 @@ export function NotificationsListener() {
 
   // This component doesn't render anything visible
   return null;
-}
+}