fix(safe-fetch): leave the deadline to the caller's signal

The pinned dispatchers kept undici's own 300 s header and body timers. A
local model with the response timeout set above five minutes answers a
non-streamed completion only once it is done, so its headers could take
longer than 300 s and undici dropped a call the caller still allowed; the
failure read as a bare network error. Every safeFetch call carries its own
AbortSignal.timeout, so that signal is now the one deadline.

Refs #1267

src/lib/__tests__/safe-fetch-dispatcher-timeouts.test.ts

@@ -0,0 +1,43 @@
+/**
+ * #1267 — the pinned dispatchers leave the deadline to the caller's signal.
+ *
+ * undici's Agent arms its own 300 s header timer and 300 s body timer by
+ * default. A local model with the response timeout at 600 s answers a
+ * non-streamed completion only once it is done, so its headers can arrive
+ * after 300 s: undici then dropped a call the caller still allowed, and the
+ * failure read as a bare network error. Waiting five minutes in a unit test
+ * proves nothing faster, so this reads the options the Agent was built with.
+ */
+import { afterEach, describe, expect, it } from "vitest";
+import type { Agent } from "undici";
+import {
+  getPinnedOperatorApprovedDispatcher,
+  getPinnedPublicDispatcher,
+  _resetPinnedDispatcherForTests,
+} from "../safe-fetch-dispatcher";
+
+function agentOptions(agent: Agent): {
+  headersTimeout?: number;
+  bodyTimeout?: number;
+} {
+  const key = Object.getOwnPropertySymbols(agent).find(
+    (s) => s.description === "options",
+  );
+  expect(key).toBeDefined();
+  return (agent as unknown as Record<symbol, Record<string, number>>)[key!];
+}
+
+afterEach(() => {
+  _resetPinnedDispatcherForTests();
+});
+
+describe("pinned dispatcher timers", () => {
+  it.each([
+    ["public", getPinnedPublicDispatcher],
+    ["operator-approved", getPinnedOperatorApprovedDispatcher],
+  ])("the %s dispatcher arms no header or body timer of its own", (_, get) => {
+    const options = agentOptions(get());
+    expect(options.headersTimeout).toBe(0);
+    expect(options.bodyTimeout).toBe(0);
+  });
+});

src/lib/safe-fetch-dispatcher.ts

@@ -147,6 +147,14 @@ let cachedOperatorApproved: Agent | null = null;
 
 function createPinnedDispatcher(policy: AddressPolicy): Agent {
   return new Agent({
+    // #1267 — undici's own 300 s header and body timers would cut a call the
+    // caller allowed longer: a local model with a 600 s response timeout
+    // answers a non-streamed completion only when it is done, so its headers
+    // can take longer than 300 s, and the failure surfaced as a bare
+    // "network" error. Every `safeFetch` call carries its own
+    // `AbortSignal.timeout`, so that signal is the one deadline.
+    headersTimeout: 0,
+    bodyTimeout: 0,
     connect: {
       lookup:
         policy === "public" ? pinnedPublicLookup : pinnedOperatorApprovedLookup,