feat/idea: hide an Easter Egg message in `README.md`

[glaucia86]

🎯 Goal:

We will hide a secret message inside README.md that hints at the Easter Egg. Users who find it will be guided to a hidden challenge.

---

🛠 Steps to Implement:

1. Inside README.md, add this hidden comment:

<!-- 🏺 The Lost Scroll of Alexandria 🏺
Congratulations, traveler! You have uncovered an ancient secret.
To reveal its true power, run:

npm run decipher-scroll

And enter the code: "ALEXANDRIA-300BC"
-->

2. Ensure this message does not appear in normal rendering.
3. Test by checking that users can only see it when inspecting the Markdown source.

✅ Expected Outcome: users who inspect the README will find this hidden clue and be directed to the next part of the challenge

---