fix(crypto): hkdf callback should pass null (not undefined) on success (#23216)

## Summary
- Fixed crypto.hkdf callback to pass `null` instead of `undefined` for
the error parameter on success
- Added regression test to verify the fix

## Details

Fixes #23211

Node.js convention requires crypto callbacks to receive `null` as the
error parameter on success, but Bun was passing `undefined`. This caused
compatibility issues with code that relies on strict null checks (e.g.,
[matter.js](fdbec2cf88/packages/general/src/crypto/NodeJsStyleCrypto.ts (L169))).

### Changes
- Updated `CryptoHkdf.cpp` to pass `jsNull()` instead of `jsUndefined()`
for the error parameter in the success callback
- Added regression test in `test/regression/issue/23211.test.ts`

## Test plan
- [x] Added regression test that verifies callback receives `null` on
success
- [x] Test passes with the fix
- [x] Ran existing crypto tests (no failures)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Dylan Conway <dylan.conway567@gmail.com>

src/bun.js/bindings/node/crypto/CryptoHkdf.cpp

@@ -97,7 +97,7 @@ void HkdfJobCtx::runFromJS(JSGlobalObject* lexicalGlobalObject, JSValue callback
     Bun__EventLoop__runCallback2(lexicalGlobalObject,
         JSValue::encode(callback),
         JSValue::encode(jsUndefined()),
-        JSValue::encode(jsUndefined()),
+        JSValue::encode(jsNull()),
         JSValue::encode(JSArrayBuffer::create(vm, globalObject->arrayBufferStructure(), buf.releaseNonNull())));
 }
 

test/js/node/crypto/hkdf-callback-null.test.ts

@@ -0,0 +1,23 @@
+import { expect, test } from "bun:test";
+import crypto from "node:crypto";
+
+// Test that callback receives null (not undefined) for error on success
+// https://github.com/oven-sh/bun/issues/23211
+test("crypto.hkdf callback should pass null (not undefined) on success", async () => {
+  const secret = new Uint8Array([7, 158, 216, 197, 25, 77, 201, 5, 73, 119]);
+  const salt = new Uint8Array([0, 0, 0, 0, 0, 0, 0, 1]);
+  const info = new Uint8Array([67, 111, 109, 112, 114, 101, 115, 115, 101, 100]);
+  const length = 8;
+
+  const promise = new Promise((resolve, reject) => {
+    crypto.hkdf("sha256", secret, salt, info, length, (error, key) => {
+      // Node.js passes null for error on success, not undefined
+      expect(error).toBeNull();
+      expect(error).not.toBeUndefined();
+      expect(key).toBeInstanceOf(ArrayBuffer);
+      resolve(true);
+    });
+  });
+
+  await promise;
+});

test/regression/issue/23183.test.ts

@@ -1,8 +1,7 @@
 // https://github.com/oven-sh/bun/issues/23183
 // Test that accessing process.title doesn't crash on Windows
-import { test, expect } from "bun:test";
-import { bunExe, bunEnv, isWindows } from "harness";
-import { join } from "path";
+import { expect, test } from "bun:test";
+import { bunEnv, bunExe, isWindows } from "harness";
 
 test("process.title should not crash on Windows", async () => {
   const proc = Bun.spawn({