[S2T04] Add Easter Egg Notification

[agnt-platform]

Display a subtle message on the site (e.g., 'Пасхалка ждет тебя!') to hint users about the easter egg. Files: index.html, style.css. Test by verifying the message is visible and clear.

Reward: 10 BTTN + 0.01 TON · Weight: 0.1000 · Difficulty: easy