v1.6.0

Highlights

• Upgrade Gradle to 9.0.0, then 9.4.0
• Update Kotlin, Ktor, kotest 6.0.0, readingbat 3.0.5, utils 2.4.2
• Add shadowJar config and test logging
• Update Java runtime to 17 and remove redisEnabled config
• Fix tests by adding initTestProperties and ktor-server-config-yaml
• Migrate packages from JitPack to Maven Central
• Update readingbat to 3.1.2, adjust group ID
• Modernize README, add CLAUDE.md and llms.txt
• Add .DS_Store to .gitignore
• Fix unreachable slice1.py

Full Changelog: 1.5.0...1.6.0