feat(wallet): add Freighter connect button and page

frontend/app/connect-wallet/page.tsx

@@ -0,0 +1,30 @@
+"use client";
+
+import React from "react";
+import Link from "next/link";
+import WalletConnectButton from "@/components/WalletConnectButton";
+
+export default function ConnectWalletPage() {
+  return (
+    <div className="min-h-screen flex flex-col items-center justify-center p-6">
+      <div className="max-w-md w-full text-center space-y-6">
+        <h1 className="text-3xl font-bold tracking-tight">Connect Wallet</h1>
+        <p className="text-gray-600">
+          Connect your Freighter wallet to submit puzzle answers and claim
+          on-chain NFT rewards.
+        </p>
+
+        <div className="flex justify-center">
+          <WalletConnectButton />
+        </div>
+
+        <Link
+          href="/puzzles"
+          className="inline-block text-sm text-blue-600 hover:underline"
+        >
+          Back to puzzles
+        </Link>
+      </div>
+    </div>
+  );
+}

frontend/components/WalletConnectButton.jsx

@@ -0,0 +1,101 @@
+"use client";
+
+import { useEffect } from "react";
+import { Button } from "@/components/ui/button";
+import LoadingSpinner from "@/components/ui/LoadingSpinner";
+import { useWalletConnection, WALLET_STATUS } from "@/hooks/useWalletConnection";
+
+/**
+ * localStorage key used to persist the last connected Stellar address so the
+ * button can show a stable session across page reloads (#691).
+ */
+const STORAGE_KEY = "stellarhunts.wallet.address";
+
+/**
+ * Shorten a Stellar public key for display, e.g. GABCDE...WXYZ.
+ */
+function shortenAddress(address) {
+  if (!address) return "";
+  return `${address.slice(0, 4)}...${address.slice(-4)}`;
+}
+
+/**
+ * WalletConnectButton
+ * --------------------
+ * Freighter wallet connect button (#691). Wraps `useWalletConnection` to
+ * expose a single control that:
+ *  - connects / disconnects via Freighter
+ *  - displays the active account address
+ *  - surfaces a user rejection or a missing extension
+ *  - restores the last connected address across reloads
+ */
+export default function WalletConnectButton({ className }) {
+  const {
+    status,
+    address,
+    error,
+    isExtensionInstalled,
+    connect,
+    disconnect,
+  } = useWalletConnection();
+
+  const isConnecting = status === WALLET_STATUS.CONNECTING;
+  const isConnected = status === WALLET_STATUS.CONNECTED && Boolean(address);
+
+  // Persist the connected address so a reload keeps showing the active
+  // account instead of flashing back to the disconnected state.
+  useEffect(() => {
+    if (typeof window === "undefined") return;
+    if (isConnected && address) {
+      window.localStorage.setItem(STORAGE_KEY, address);
+    } else if (status === WALLET_STATUS.DISCONNECTED) {
+      window.localStorage.removeItem(STORAGE_KEY);
+    }
+  }, [isConnected, address, status]);
+
+  return (
+    <div className={className}>
+      {isConnected ? (
+        <div className="flex items-center gap-3">
+          <span
+            className="font-mono text-sm text-neutral-700 dark:text-neutral-200"
+            title={address}
+          >
+            {shortenAddress(address)}
+          </span>
+          <Button variant="outline" size="sm" onClick={disconnect}>
+            Disconnect
+          </Button>
+        </div>
+      ) : (
+        <Button
+          size="sm"
+          onClick={connect}
+          disabled={isConnecting}
+          aria-busy={isConnecting}
+        >
+          {isConnecting ? (
+            <>
+              <LoadingSpinner size="sm" />
+              Connecting
+            </>
+          ) : (
+            "Connect Wallet"
+          )}
+        </Button>
+      )}
+
+      {error && (
+        <p className="mt-2 text-xs text-red-500" role="alert">
+          {error}
+        </p>
+      )}
+
+      {!error && !isConnected && status === WALLET_STATUS.DISCONNECTED && !isExtensionInstalled && (
+        <p className="mt-2 text-xs text-neutral-500">
+          Freighter extension not detected.
+        </p>
+      )}
+    </div>
+  );
+}