fix: honor Telegram proxy dispatcher (#4456) (thanks @spiceoogway)

CHANGELOG.md

@@ -72,6 +72,7 @@ Status: stable.
 - **BREAKING:** Gateway auth mode "none" is removed; gateway now requires token/password (Tailscale Serve identity still allowed).
 
 ### Fixes
+- Telegram: use undici fetch for per-account proxy dispatcher. (#4456) Thanks @spiceoogway.
 - Telegram: avoid silent empty replies by tracking normalization skips before fallback. (#3796)
 - Telegram: scope native skill commands to bound agent per bot. (#4360) Thanks @robhparker.
 - Mentions: honor mentionPatterns even when explicit mentions are present. (#3303) Thanks @HirokiKobayashi-R.

src/telegram/proxy.test.ts

@@ -0,0 +1,45 @@
+import { describe, expect, it, vi } from "vitest";
+
+const { ProxyAgent, undiciFetch, proxyAgentSpy, getLastAgent } = vi.hoisted(() => {
+  const undiciFetch = vi.fn();
+  const proxyAgentSpy = vi.fn();
+  class ProxyAgent {
+    static lastCreated: ProxyAgent | undefined;
+    proxyUrl: string;
+    constructor(proxyUrl: string) {
+      this.proxyUrl = proxyUrl;
+      ProxyAgent.lastCreated = this;
+      proxyAgentSpy(proxyUrl);
+    }
+  }
+
+  return {
+    ProxyAgent,
+    undiciFetch,
+    proxyAgentSpy,
+    getLastAgent: () => ProxyAgent.lastCreated,
+  };
+});
+
+vi.mock("undici", () => ({
+  ProxyAgent,
+  fetch: undiciFetch,
+}));
+
+import { makeProxyFetch } from "./proxy.js";
+
+describe("makeProxyFetch", () => {
+  it("uses undici fetch with ProxyAgent dispatcher", async () => {
+    const proxyUrl = "http://proxy.test:8080";
+    undiciFetch.mockResolvedValue({ ok: true });
+
+    const proxyFetch = makeProxyFetch(proxyUrl);
+    await proxyFetch("https://api.telegram.org/bot123/getMe");
+
+    expect(proxyAgentSpy).toHaveBeenCalledWith(proxyUrl);
+    expect(undiciFetch).toHaveBeenCalledWith(
+      "https://api.telegram.org/bot123/getMe",
+      expect.objectContaining({ dispatcher: getLastAgent() }),
+    );
+  });
+});