Add examples

examples/ecdh-wraps-key.test.ts

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