Add examples

examples/key-wraps-ecdh.test.ts

@@ -0,0 +1,14 @@
+import {expect} from 'bun:test'
+
+import {SecretWrap, PrivateWrap} from '../index'
+
+const key_wraps = await SecretWrap.gen_key()
+const key_wrapped = await PrivateWrap.gen_keypair()
+
+const cipher = await SecretWrap.encrypt(key_wrapped.privateKey, key_wraps)
+const box = cipher.toString()
+const unbox = SecretWrap.fromString(box)
+const plain = await unbox.decrypt(key_wraps)
+
+expect(plain).toEqual(key_wrapped.privateKey)
+console.log("key-wraps-ecdh OK")