Add WalletProvider

app/src/state/wallet.tsx

@@ -0,0 +1,44 @@
+import type { JSX, PropsWithChildren } from "react";
+import { createContext, useCallback, useContext, useMemo, useState } from "react";
+
+export type WalletName = "phantom" | "solflare" | "backpack";
+
+const WALLET_ADDRESSES: Record<WalletName, string> = {
+  phantom: "Gh9Z…k3mP",
+  solflare: "Bx3K…7pRq",
+  backpack: "Kx7P…2mJc",
+};
+
+interface WalletContextValue {
+  connected: boolean;
+  address: string | null;
+  connect: (wallet: WalletName) => void;
+  disconnect: () => void;
+}
+
+const WalletContext = createContext<WalletContextValue | null>(null);
+
+export function WalletProvider({ children }: PropsWithChildren): JSX.Element {
+  const [address, setAddress] = useState<string | null>(null);
+
+  const connect = useCallback((wallet: WalletName) => {
+    setAddress(WALLET_ADDRESSES[wallet]);
+  }, []);
+
+  const disconnect = useCallback(() => {
+    setAddress(null);
+  }, []);
+
+  const value = useMemo<WalletContextValue>(
+    () => ({ connected: address !== null, address, connect, disconnect }),
+    [address, connect, disconnect],
+  );
+
+  return <WalletContext.Provider value={value}>{children}</WalletContext.Provider>;
+}
+
+export function useWallet(): WalletContextValue {
+  const ctx = useContext(WalletContext);
+  if (!ctx) throw new Error("useWallet must be used within a WalletProvider");
+  return ctx;
+}