feat(proxy): add proxy pool and per-connection binding + strictProxy support

- Centralize proxy management with reusable proxy pools
- Per-connection proxy binding with legacy fallback
- Add strictProxy option: fail hard instead of silently falling back to direct
- Resolve alicode-intl conflict: keep alicode-intl support + proxy support

Made-with: Cursor

open-sse/executors/base.js

@@ -1,4 +1,5 @@
 import { HTTP_STATUS } from "../config/constants.js";
+import { proxyAwareFetch } from "../utils/proxyFetch.js";
 
 /**
  * BaseExecutor - Base class for provider executors
@@ -75,7 +76,7 @@ export class BaseExecutor {
     return { status: response.status, message: bodyText || `HTTP ${response.status}` };
   }
 
-  async execute({ model, body, stream, credentials, signal, log }) {
+  async execute({ model, body, stream, credentials, signal, log, proxyOptions = null }) {
     const fallbackCount = this.getFallbackCount();
     let lastError = null;
     let lastStatus = 0;
@@ -86,12 +87,12 @@ export class BaseExecutor {
       const transformedBody = this.transformRequest(model, body, stream, credentials);
 
       try {
-        const response = await fetch(url, {
+        const response = await proxyAwareFetch(url, {
           method: "POST",
           headers,
           body: JSON.stringify(transformedBody),
           signal
-        });
+        }, proxyOptions);
 
         if (this.shouldRetry(response.status, urlIndex)) {
           log?.debug?.("RETRY", `${response.status} on ${url}, trying fallback ${urlIndex + 1}`);