feat(claude): merge client anthropic-beta flags and forward rate-limit headers

open-sse/handlers/chatCore.js

@@ -9,6 +9,7 @@ import { createRequestLogger } from "../utils/requestLogger.js";
 import { getModelTargetFormat, getModelSupportedFormats, getModelStrip, getModelUpstreamId, getModelType, PROVIDER_ID_TO_ALIAS } from "../config/providerModels.js";
 import { PROVIDERS } from "../config/providers.js";
 import { createErrorResult, parseUpstreamError, formatProviderError } from "../utils/error.js";
+import { upstreamResponseHeaders } from "../utils/upstreamHeaders.js";
 import { HTTP_STATUS, TOKEN_SAVER_HEADER } from "../config/runtimeConfig.js";
 import { handleBypassRequest } from "../utils/bypassHandler.js";
 import { trackPendingRequest, appendRequestLog, saveRequestDetail } from "@/lib/usageDb.js";
@@ -486,7 +487,7 @@ export async function handleChatCore({ body, modelInfo, credentials, log, onCred
       log.errorLine(reqTag, "✗", `ERROR ${statusCode} · ${provider}/${model} · ${Date.now() - requestStartTime}ms${urlStr}\n    ${errMsg}`);
     }
     reqLogger.logError(new Error(message), finalBody || translatedBody);
-    return createErrorResult(statusCode, errMsg, resetsAtMs);
+    return createErrorResult(statusCode, errMsg, resetsAtMs, upstreamResponseHeaders(providerResponse.headers));
   }
 
   const sharedCtx = { provider, model, body, stream, translatedBody, finalBody, requestStartTime, connectionId, apiKey, clientRawRequest, onRequestSuccess, pxpipe: pxpipeSummary, reqTag, log };