feat: add chain API wrapper with idempotency-key

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/api/chain.js

@@ -0,0 +1,72 @@
+import { apiFetch } from './client';
+
+const BASE = import.meta.env.VITE_API_BASE_URL || '';
+
+// --- 지갑 ---
+export async function getBalance() {
+  return apiFetch('/api/chain/balance');
+}
+
+export async function getWallet() {
+  return apiFetch('/api/chain/wallet');
+}
+
+// 키 내보내기는 비밀번호 오류 시 서버가 401을 반환하므로,
+// apiFetch의 401 자동 refresh/로그아웃을 우회하기 위해 직접 fetch한다.
+export async function exportWalletKey(password) {
+  const token = localStorage.getItem('token');
+  const headers = { 'Content-Type': 'application/json' };
+  if (token) headers['Authorization'] = `Bearer ${token}`;
+  const res = await fetch(BASE + '/api/chain/wallet/export', {
+    method: 'POST',
+    headers,
+    credentials: 'include',
+    body: JSON.stringify({ password }),
+  });
+  if (!res.ok) {
+    const err = new Error(res.status === 401 ? '비밀번호가 올바르지 않습니다' : '키 내보내기에 실패했습니다');
+    err.status = res.status;
+    try { const body = await res.json(); err.message = body.message || err.message; } catch {}
+    throw err;
+  }
+  return res.json();
+}
+
+// --- 자산 ---
+export async function getAssets() {
+  return apiFetch('/api/chain/assets');
+}
+
+export async function getAsset(id) {
+  return apiFetch(`/api/chain/asset/${id}`);
+}
+
+// --- 인벤토리 ---
+export async function getInventory() {
+  return apiFetch('/api/chain/inventory');
+}
+
+// --- 마켓 ---
+export async function getMarketListings() {
+  return apiFetch('/api/chain/market');
+}
+
+function idempotentPost(path, body) {
+  return apiFetch(path, {
+    method: 'POST',
+    headers: { 'Idempotency-Key': crypto.randomUUID() },
+    body: JSON.stringify(body),
+  });
+}
+
+export async function listOnMarket(assetId, price) {
+  return idempotentPost('/api/chain/market/list', { asset_id: assetId, price });
+}
+
+export async function buyFromMarket(listingId) {
+  return idempotentPost('/api/chain/market/buy', { listing_id: listingId });
+}
+
+export async function cancelListing(listingId) {
+  return idempotentPost('/api/chain/market/cancel', { listing_id: listingId });
+}