Kotlin-only reference repo — move the app's main/test/androidTest source roots
from src/main/java to src/main/kotlin (the core/feature modules already use kotlin).
Verified: :app:compileDebugKotlin produces MainActivity from src/main/kotlin.
Foundation milestone (REDI-78, REDI-79):
- Multi-module skeleton: :app, :core:{domain,data,presentation,design-system},
:feature:characters:{domain,data,presentation,presentation-compose,presentation-views},
:feature:about:presentation, plus the :build-logic composite build.
- gradle/libs.versions.toml as the single source of truth ([versions]/[libraries]/
[bundles]/[plugins]); no inline versions in any build file.
- Convention plugins: architecture.android.{application,library,feature,feature.views},
domain.module, compose, koin, ktor, kotlinx.serialization.
- Pure-Kotlin domain modules; presentation-compose uses android.feature;
presentation-views uses android.feature.views (ViewBinding on, Compose off);
the UI-agnostic :presentation has neither Compose nor Views deps.
- Toolchain: AGP 9.0.1, Kotlin 2.3.20, Gradle 9.1.0, compileSdk 36, minSdk 24, Java 17.
- Minimal MainActivity placeholder; CI (assembleDebug) via GitHub Actions.
Verified: ./gradlew projects lists the full tree and ./gradlew assemble is green.
