fix(crypto): support structuredClone for CryptoKey

Uses the cloneable resource registry from denoland#32672 to enable structured
cloning of CryptoKey objects. This allows CryptoKeys (including
non-extractable ones) to be passed to Workers via postMessage and
cloned with structuredClone().

Closes denoland#12734

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: bartlomieju

ext/crypto/00_crypto.js

@@ -438,9 +438,29 @@ function constructKey(type, extractable, usages, algorithm, handle) {
   key[_algorithm] = algorithm;
   key[_handle] = handle;
   key[kKeyObject] = WeakMapPrototypeGet(KEY_STORE, handle);
+  key[core.hostObjectBrand] = () => ({
+    type: "CryptoKey",
+    keyType: type,
+    extractable,
+    usages,
+    algorithm,
+    keyData: WeakMapPrototypeGet(KEY_STORE, handle),
+  });
   return key;
 }
 
+core.registerCloneableResource("CryptoKey", (data) => {
+  const handle = {};
+  WeakMapPrototypeSet(KEY_STORE, handle, data.keyData);
+  return constructKey(
+    data.keyType,
+    data.extractable,
+    data.usages,
+    data.algorithm,
+    handle,
+  );
+});
+
 // https://w3c.github.io/webcrypto/#concept-usage-intersection
 /**
  * @param {string[]} a