refactor: rename email-server-worker to email-worker

Rename directory from email-server-worker to email-worker for clarity and brevity. Update all references in CLAUDE.md documentation.

email-worker/sent-mail-tester.mjs

@@ -0,0 +1,27 @@
+import FormData from "form-data"; // form-data v4.0.1
+import Mailgun from "mailgun.js"; // mailgun.js v11.1.0
+
+async function sendSimpleMessage() {
+  const mailgun = new Mailgun(FormData);
+  const mg = mailgun.client({
+    username: "api",
+    key: process.env.API_KEY || "f581edcac21ec14d086ef25e36f04432-e61ae8dd-e207f22b",
+    // When you have an EU-domain, you must specify the endpoint:
+    url: "https://api.eu.mailgun.net"
+  });
+  try {
+    console.log("Sending email...");
+    const data = await mg.messages.create("rezije.app", {
+      from: "Mailgun Sandbox <support@rezije.app>",
+      to: ["Nikola Derezic <nikola.derezic@gmail.com>"],
+      subject: "Hello Nikola Derezic",
+      text: "Congratulations Nikola Derezic, you just sent an email with Mailgun! You are truly awesome!",
+    });
+
+    console.log(data); // logs response data
+  } catch (error) {
+    console.log(error); //logs any error
+  }
+}
+
+sendSimpleMessage();