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

open-sse/handlers/chatCore/nonStreamingHandler.js

@@ -4,6 +4,7 @@ import { fromOpenAIFinish } from "../../translator/concerns/finishReason.js";
 import { ollamaBodyToOpenAI } from "../../translator/response/ollama-to-openai.js";
 import { addBufferToUsage, filterUsageForFormat } from "../../utils/usageTracking.js";
 import { createErrorResult } from "../../utils/error.js";
+import { upstreamResponseHeaders } from "../../utils/upstreamHeaders.js";
 import { HTTP_STATUS } from "../../config/runtimeConfig.js";
 import { parseSSEToOpenAIResponse } from "./sseToJsonHandler.js";
 import { unwrapClineEnvelope } from "../../shared/clineEnvelope.js";
@@ -399,7 +400,7 @@ export async function handleNonStreamingResponse({ providerResponse, provider, m
   return {
     success: true,
     response: new Response(JSON.stringify(restoreToolNames(translatedResponse, toolNameMap)), {
-      headers: { "Content-Type": "application/json", "Access-Control-Allow-Origin": "*" }
+      headers: { "Content-Type": "application/json", "Access-Control-Allow-Origin": "*", ...upstreamResponseHeaders(providerResponse.headers) }
     })
   };
 }

open-sse/handlers/chatCore/streamingHandler.js

@@ -9,6 +9,7 @@ import { buildStreamErrorBytes } from "../../utils/streamHelpers.js";
 import { buildRequestDetail, extractRequestConfig, saveUsageStats, formatDoneLine } from "./requestDetail.js";
 import { saveRequestDetail } from "@/lib/usageDb.js";
 import { SSE_HEADERS_CORS as SSE_HEADERS } from "../../utils/sseConstants.js";
+import { upstreamResponseHeaders } from "../../utils/upstreamHeaders.js";
 
 // Codex returns Responses API SSE → which client format to translate INTO, by request sourceFormat.
 // Gemini-family all map to ANTIGRAVITY decoder; unknown sources fall back to OPENAI.
@@ -109,7 +110,7 @@ export async function handleStreamingResponse({ providerResponse, provider, mode
 
   return {
     success: true,
-    response: new Response(transformedBody, { headers: SSE_HEADERS })
+    response: new Response(transformedBody, { headers: { ...SSE_HEADERS, ...upstreamResponseHeaders(providerResponse.headers) } })
   };
 }