fix: NVIDIA NIM API key validation timeout (bypass proxy fetch patch) (#3226)

NVIDIA NIM validation bypasses the proxy-patched fetch (504 fix) + combined with #3116 reliable probe model + test. Integrated into release/v3.8.11.

tests/unit/nvidia-validation-bypass-proxy-3226.test.ts

@@ -0,0 +1,59 @@
+/**
+ * #3226 — NVIDIA NIM validation must be able to bypass the global proxy/TLS
+ * patched fetch (the undici dispatcher stalls against NVIDIA's endpoint → 504).
+ *
+ * The mechanism: `safeOutboundFetch({ bypassProxyPatch: true })` resolves the
+ * native fetch via `getOriginalFetch()` and threads it to `fetchWithTimeout`
+ * as `fetchFn`, which calls it instead of the (patched) `globalThis.fetch`.
+ * These tests guard the wiring at its two seams.
+ */
+import test from "node:test";
+import assert from "node:assert/strict";
+
+const { fetchWithTimeout } = await import("../../src/shared/utils/fetchTimeout.ts");
+const { getOriginalFetch } = await import("../../open-sse/utils/proxyFetch.ts");
+
+const originalGlobalFetch = globalThis.fetch;
+
+test.afterEach(() => {
+  globalThis.fetch = originalGlobalFetch;
+});
+
+test("#3226 fetchWithTimeout uses the provided fetchFn instead of globalThis.fetch", async () => {
+  let globalCalled = false;
+  let fnCalled = false;
+  globalThis.fetch = async () => {
+    globalCalled = true;
+    return Response.json({ via: "global" });
+  };
+  const customFetch = (async () => {
+    fnCalled = true;
+    return Response.json({ via: "custom" });
+  }) as unknown as typeof globalThis.fetch;
+
+  const res = await fetchWithTimeout("https://integrate.api.nvidia.com/v1/chat/completions", {
+    method: "POST",
+    timeoutMs: 100,
+    fetchFn: customFetch,
+  });
+
+  assert.equal(fnCalled, true, "provided fetchFn must be used");
+  assert.equal(globalCalled, false, "patched globalThis.fetch must be bypassed");
+  assert.deepEqual(await res.json(), { via: "custom" });
+});
+
+test("#3226 fetchWithTimeout falls back to globalThis.fetch when no fetchFn is given", async () => {
+  let globalCalled = false;
+  globalThis.fetch = async () => {
+    globalCalled = true;
+    return Response.json({ via: "global" });
+  };
+
+  await fetchWithTimeout("https://example.test/x", { method: "GET", timeoutMs: 100 });
+  assert.equal(globalCalled, true);
+});
+
+test("#3226 getOriginalFetch returns a callable native fetch (the un-patched reference)", () => {
+  const native = getOriginalFetch();
+  assert.equal(typeof native, "function");
+});