Migrate Addendum with open-source-library-migration guide

[theJawnnybot]

Summary

Applied open-source-library-migration.md to Addendum (multi-module).

Build/toolchain

• Java 17
• Gradle 9.3.1
• AGP 9.1.0
• Kotlin 2.3.10 plugin declarations in root
• Converted all Gradle scripts to Kotlin DSL (.gradle.kts)
• Updated dependencies to current stable versions

Publishing (multi-module)

Configured Maven Central publishing for:

• addendum
• addendum-design
• addendum-recyclerview
• addendum-parceler
• addendum-threetenabp

Using com.vanniktech.maven.publish with:

• publishToMavenCentral(SonatypeHost.CENTRAL_PORTAL)
• signing enabled for release workflow

CI/CD

• Added modern ci.yml with wrapper validation
• Added tag-based publish-release.yml
• Publish uses tag version arg (no file mutation):
  • -PVERSION_NAME="${GITHUB_REF_NAME}"
• Uses repo secrets:
  • MAVEN_CENTRAL_USERNAME
  • MAVEN_CENTRAL_PASSWORD
  • SIGNING_PRIVATE_KEY
  • SIGNING_PASSWORD

Docs/cleanup

• Removed Travis workflow usage
• Replaced JitPack README instructions with Maven Central coordinates
• Added Maven Central badge

Version

• Patch bump to VERSION_NAME=1.0.1

Validation

• GRADLE_USER_HOME=/tmp/gradle-addendum ./gradlew build ✅