feat(ui): add modal functionality, leaderboard view

context/ModalContext.tsx

@@ -0,0 +1,24 @@
+"use client";
+import { createContext, useContext, useState } from "react";
+
+const ModalContext = createContext(null);
+
+export function ModalProvider({ children }) {
+  const [isOpen, setIsOpen] = useState(false);
+
+  const open = () => setIsOpen(true);
+  const close = () => setIsOpen(false);
+  const toggle = () => setIsOpen((prev) => !prev);
+
+  return (
+    <ModalContext.Provider value={{ isOpen, open, close, toggle }}>
+      {children}
+    </ModalContext.Provider>
+  );
+}
+
+export function useModal() {
+  const ctx = useContext(ModalContext);
+  if (!ctx) throw new Error("useModal must be inside <ModalProvider>");
+  return ctx;
+}