Migrate AdapterLayout with open-source-library-migration guide

[theJawnnybot]

Summary

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

Build/toolchain

• Java 17
• Gradle 9.3.1 (wrapper refreshed)
• AGP 9.1.0
• Kotlin plugin declaration updated in root (2.3.10)
• Migrated all Gradle scripts from Groovy to Kotlin DSL (.gradle.kts)
• Updated dependencies to current stable versions where appropriate

Publishing (multi-module)

Configured Maven Central publishing via com.vanniktech.maven.publish for:

• adapterlayout
• adapterflowlayout
• adapterlayout-kotlin

Using:

• publishToMavenCentral(SonatypeHost.CENTRAL_PORTAL)
• signing gate via RELEASE_SIGNING_ENABLED

CI/CD

• Replaced Travis with GitHub Actions CI
• Added wrapper validation action
• Added tag-based publish workflow using:
  • MAVEN_CENTRAL_USERNAME
  • MAVEN_CENTRAL_PASSWORD
  • SIGNING_PRIVATE_KEY
  • SIGNING_PASSWORD
• Uses tag version argument (no file mutation):
  • -PVERSION_NAME="${GITHUB_REF_NAME}"

Docs/cleanup

• Removed JitPack/Travis badges and instructions
• Added Maven Central + CI badges
• Updated dependency snippets to Maven Central coordinates

Version

• Patch bump: VERSION_NAME=1.2.1

Validation

• ./gradlew build ✅
• Publish tasks exist for all three library modules ✅