Clarify receive requests and add retry countdowns and device unblock controls

apps/web/src/client.js

@@ -26,6 +26,7 @@ export const device = ref(null),
   discoveryEnabled = ref(false),
   error = ref('');
 export const pendingPeers = ref([]);
+export const transferCooldown = ref({ until: 0, targetDeviceId: null });
 let pendingTimer;
 let deviceInfo = {};
 export const nextCursor = ref(null);
@@ -60,11 +61,28 @@ export async function api(path, method = 'GET', body, key, signal) {
     body: body !== undefined ? JSON.stringify(body) : undefined,
   });
   const payload = await response.json();
-  if (!response.ok)
+  if (!response.ok) {
+    const retryAfterSeconds = Number(
+      payload.retryAfterSeconds ?? response.headers.get('Retry-After'),
+    );
+    if (
+      response.status === 429 &&
+      retryAfterSeconds > 0 &&
+      Number.isFinite(retryAfterSeconds) &&
+      method === 'POST' &&
+      (path === '/transfer-requests' || /^\/vault\/[^/]+\/send$/.test(path))
+    ) {
+      transferCooldown.value = {
+        until: Date.now() + Math.ceil(retryAfterSeconds) * 1000,
+        targetDeviceId: payload.limitScope === 'pair' ? body?.targetDeviceId : null,
+      };
+    }
     throw Object.assign(new Error(payload.message ?? '요청을 처리하지 못했습니다.'), {
       status: response.status,
       code: payload.code,
+      retryAfterSeconds,
     });
+  }
   return payload;
 }
 export async function bootstrap() {
@@ -154,9 +172,13 @@ export function showError(err) {
   const message = /^(Failed to fetch|NetworkError|Load failed)$/i.test(raw)
     ? '서버에 연결하지 못했어요. 잠시 후 다시 시도해 주세요.'
     : raw;
-  error.value = message;
+  const displayed =
+    err?.retryAfterSeconds > 0
+      ? `${message} ${Math.ceil(err.retryAfterSeconds)}초 후 다시 시도할 수 있어요.`
+      : message;
+  error.value = displayed;
   errorTimer = setTimeout(() => {
-    if (error.value === message) error.value = '';
+    if (error.value === displayed) error.value = '';
   }, 5000);
 }
 export const refresh = createRefreshQueue(async () => {