fix(telegram): move network fallback to resolver-scoped dispatchers (#40740)

Merged via squash.

Prepared head SHA: a4456d48b4
Co-authored-by: sircrumpet <4436535+sircrumpet@users.noreply.github.com>
Co-authored-by: obviyus <22031114+obviyus@users.noreply.github.com>
Reviewed-by: @obviyus

src/infra/net/proxy-fetch.test.ts

@@ -48,6 +48,7 @@ describe("makeProxyFetch", () => {
     undiciFetch.mockResolvedValue({ ok: true });
 
     const proxyFetch = makeProxyFetch(proxyUrl);
+    expect(proxyAgentSpy).not.toHaveBeenCalled();
     await proxyFetch("https://api.example.com/v1/audio");
 
     expect(proxyAgentSpy).toHaveBeenCalledWith(proxyUrl);

src/infra/net/proxy-fetch.ts

@@ -1,19 +1,46 @@
 import { EnvHttpProxyAgent, ProxyAgent, fetch as undiciFetch } from "undici";
 import { logWarn } from "../../logger.js";
 
+export const PROXY_FETCH_PROXY_URL = Symbol.for("openclaw.proxyFetch.proxyUrl");
+type ProxyFetchWithMetadata = typeof fetch & {
+  [PROXY_FETCH_PROXY_URL]?: string;
+};
+
 /**
  * Create a fetch function that routes requests through the given HTTP proxy.
  * Uses undici's ProxyAgent under the hood.
  */
 export function makeProxyFetch(proxyUrl: string): typeof fetch {
-  const agent = new ProxyAgent(proxyUrl);
+  let agent: ProxyAgent | null = null;
+  const resolveAgent = (): ProxyAgent => {
+    if (!agent) {
+      agent = new ProxyAgent(proxyUrl);
+    }
+    return agent;
+  };
   // undici's fetch is runtime-compatible with global fetch but the types diverge
   // on stream/body internals. Single cast at the boundary keeps the rest type-safe.
-  return ((input: RequestInfo | URL, init?: RequestInit) =>
+  const proxyFetch = ((input: RequestInfo | URL, init?: RequestInit) =>
     undiciFetch(input as string | URL, {
       ...(init as Record<string, unknown>),
-      dispatcher: agent,
-    }) as unknown as Promise<Response>) as typeof fetch;
+      dispatcher: resolveAgent(),
+    }) as unknown as Promise<Response>) as ProxyFetchWithMetadata;
+  Object.defineProperty(proxyFetch, PROXY_FETCH_PROXY_URL, {
+    value: proxyUrl,
+    enumerable: false,
+    configurable: false,
+    writable: false,
+  });
+  return proxyFetch;
+}
+
+export function getProxyUrlFromFetch(fetchImpl?: typeof fetch): string | undefined {
+  const proxyUrl = (fetchImpl as ProxyFetchWithMetadata | undefined)?.[PROXY_FETCH_PROXY_URL];
+  if (typeof proxyUrl !== "string") {
+    return undefined;
+  }
+  const trimmed = proxyUrl.trim();
+  return trimmed ? trimmed : undefined;
 }
 
 /**