feat: implement useWallet hook

src/hooks/useWallet.ts

@@ -0,0 +1,59 @@
+"use client";
+
+import { useCallback, useEffect, useState } from "react";
+
+export type WalletState = {
+  address: string | null;
+  network: string | null;
+  connecting: boolean;
+  error: string | null;
+};
+
+/** Freighter / browser wallet hook (issue #5). */
+export function useWallet() {
+  const [state, setState] = useState<WalletState>({
+    address: null,
+    network: null,
+    connecting: false,
+    error: null,
+  });
+
+  const refresh = useCallback(async () => {
+    try {
+      const freighter = (window as any)?.freighterApi || (window as any)?.freighter;
+      if (!freighter) {
+        setState((s) => ({ ...s, error: "Wallet extension not found" }));
+        return;
+      }
+      const address = await freighter.getPublicKey?.() || await freighter.getAddress?.();
+      const network = await freighter.getNetwork?.();
+      setState({
+        address: address || null,
+        network: typeof network === "string" ? network : network?.network || null,
+        connecting: false,
+        error: null,
+      });
+    } catch (e) {
+      setState((s) => ({
+        ...s,
+        connecting: false,
+        error: e instanceof Error ? e.message : String(e),
+      }));
+    }
+  }, []);
+
+  const connect = useCallback(async () => {
+    setState((s) => ({ ...s, connecting: true, error: null }));
+    await refresh();
+  }, [refresh]);
+
+  const disconnect = useCallback(() => {
+    setState({ address: null, network: null, connecting: false, error: null });
+  }, []);
+
+  useEffect(() => {
+    refresh();
+  }, [refresh]);
+
+  return { ...state, connect, disconnect, refresh };
+}