🔒 Fix XSS vulnerability by removing innerHTML usage in easter egg script

[pavanbadempet]

🎯 What: This PR fixes a Cross-Site Scripting (XSS) vulnerability in assets/js/easter-egg.js.
⚠️ Risk: The previous implementation used innerHTML to set the content of the "secret" screen overlay. While currently the content is static and the risk is low, using innerHTML with dynamically constructed strings or future modifications could allow an attacker to inject malicious scripts into the application.
🛡️ Solution: Replaced the unsafe innerHTML assignments with secure DOM manipulation methods (e.g., document.createElement, textContent, and appendChild). This ensures that any data rendered inside these elements is safely escaped, mitigating any potential XSS attacks.

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PR created automatically by Jules for task 6265753529843104828 started by @pavanbadempet

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