chore(upgrade): update gradle version, update google.guava version

[xylos19]

This PR upgrades the build system and improves compatibility with modern Gradle versions.

🔧 Changes Made

• ⬆️ Upgraded Gradle wrapper from 2.11 to 8.13
  Ensures compatibility with current Java toolchains and enables modern Gradle features.

• 🔁 Replaced deprecated testCompile with testImplementation

• 📦 Added Guava dependency
  com.google.guava:guava:33.4.8-jre to resolve missing com.google.common.collect.Lists usage.

• 🧪 Updated jacocoTestReport configuration:

  • Replaced deprecated enabled = false with required.set(false)
  • Updated html.destination → outputLocation.set(...) per Gradle 8+ guidelines

📌 Motivation

• Fixes compilation issues due to missing Guava dependency
• Resolves deprecated Gradle configuration errors
• Modernizes the build setup for future maintenance and enhancements