fix and update

apps/frontend/lib/api.ts

@@ -677,13 +677,15 @@ export function buildSystemSettingPayload(setting: Pick<SystemSetting, 'key' | '
 }
 
 const GATEWAY_RETRY_STATUS = new Set([502, 503, 504]);
-const GATEWAY_RETRY_ATTEMPTS = 2;
+const GATEWAY_RETRY_ATTEMPTS = 4;
 const GATEWAY_PROBE_MAX_ATTEMPTS = 48;
 const GATEWAY_PROBE_BASE_DELAY_MS = 450;
-const API_MAX_CONCURRENT = 8;
-const API_BURST_MAX_CONCURRENT = 3;
-const API_BURST_WINDOW_MS = 3000;
+const GATEWAY_STABLE_PROBES = 3;
+const API_MAX_CONCURRENT = 6;
+const API_BURST_MAX_CONCURRENT = 2;
+const API_BURST_WINDOW_MS = 5000;
 const API_READY_EVENT = 'idp-api-ready';
+const API_NOT_READY_EVENT = 'idp-api-not-ready';
 
 function sleep(ms: number): Promise<void> {
   return new Promise((resolve) => setTimeout(resolve, ms));
@@ -703,6 +705,9 @@ export function resetApiGatewayWarmup() {
 export function invalidateApiGatewayReady() {
   gatewayReadyResolved = false;
   gatewayReadyAt = 0;
+  if (typeof window !== 'undefined') {
+    window.dispatchEvent(new CustomEvent(API_NOT_READY_EVENT));
+  }
 }
 
 export function isApiGatewayReady() {
@@ -728,6 +733,37 @@ export function subscribeApiReady(listener: () => void): () => void {
   return () => window.removeEventListener(API_READY_EVENT, listener);
 }
 
+export function subscribeApiNotReady(listener: () => void): () => void {
+  if (typeof window === 'undefined') return () => undefined;
+  window.addEventListener(API_NOT_READY_EVENT, listener);
+  return () => window.removeEventListener(API_NOT_READY_EVENT, listener);
+}
+
+/** Несколько подряд успешных /health через nginx — защита от «один OK, потом 502». */
+export async function waitForStableGateway(stableProbes = GATEWAY_STABLE_PROBES): Promise<void> {
+  if (typeof window === 'undefined') return;
+
+  gatewayReadyResolved = false;
+  gatewayReadyAt = 0;
+
+  let streak = 0;
+  for (let attempt = 0; attempt < 40 && streak < stableProbes; attempt += 1) {
+    if (await probeGatewayAlive()) {
+      streak += 1;
+      if (streak >= stableProbes) {
+        markApiGatewayReady();
+        return;
+      }
+      await sleep(400);
+    } else {
+      streak = 0;
+      await sleep(Math.min(500 + attempt * 220, 2200));
+    }
+  }
+
+  throw new ApiError('Сервер API временно недоступен. Попробуйте обновить страницу.', 503, 'GATEWAY_UNAVAILABLE');
+}
+
 async function acquireApiSlot(): Promise<void> {
   const inBurst = gatewayReadyAt > 0 && Date.now() - gatewayReadyAt < API_BURST_WINDOW_MS;
   const limit = inBurst ? API_BURST_MAX_CONCURRENT : API_MAX_CONCURRENT;
@@ -807,14 +843,24 @@ async function fetchWithGatewayRetry(url: string, init: RequestInit): Promise<Re
         markApiGatewayReady();
       }
       if (GATEWAY_RETRY_STATUS.has(response.status) && attempt + 1 < GATEWAY_RETRY_ATTEMPTS) {
-        await sleep(gatewayRetryDelay(attempt));
+        invalidateApiGatewayReady();
+        try {
+          await waitForStableGateway(2);
+        } catch {
+          await sleep(gatewayRetryDelay(attempt));
+        }
         continue;
       }
       return response;
     } catch (error) {
       lastNetworkError = error;
       if (attempt + 1 < GATEWAY_RETRY_ATTEMPTS) {
-        await sleep(gatewayRetryDelay(attempt));
+        invalidateApiGatewayReady();
+        try {
+          await waitForStableGateway(2);
+        } catch {
+          await sleep(gatewayRetryDelay(attempt));
+        }
         continue;
       }
       throw mapFetchError(error);