fix(tests): Update testing setup and bump deps; add deno.lock and combined Node/Deno/Bun test

test/test.node+deno+bun.ts

@@ -50,8 +50,10 @@ tap.test('should send a smartmail with empty body', async () => {
 });
 
 tap.test('should retrieve a mail using a retrieval url', async () => {
+  // Note: This test requires a valid message storage URL from a recently sent email
+  // Storage URLs are available for 3 days after sending via Events API or Mailgun dashboard
   const result = await testMailgunAccount.retrieveSmartMailFromMessageUrl(
-    'https://sw.api.mailgun.net/v3/domains/mail.lossless.one/messages/AgMFnnnAKC8xp_dDa79LyoxhloxtaVmnRA==',
+    'https://api.eu.mailgun.net/v3/domains/mail.lossless.one/messages/AgMFnnnAKC8xp_dDa79LyoxhloxtaVmnRA==',
   );
   console.log(result);