Update dependencies to latest stable versions

[sdeff]

Summary

• Update to AGP 9.0, Kotlin 2.3.0, Gradle 9.1.0
• Update compileSdk/targetSdk to 36
• Update AndroidX dependencies:
  • core-ktx 1.15.0 → 1.17.0
  • activity-compose 1.10.0 → 1.12.3
  • compose-material3 1.3.1 → 1.4.0
  • compose-ui-tooling 1.7.6 → 1.10.2
  • appcompat 1.7.0 → 1.7.1
  • constraintlayout 2.2.0 → 2.2.1
• Update Google Material 1.12.0 → 1.13.0
• Update ktlint-gradle 12.1.2 → 14.0.1
• Update test dependencies:
  • JUnit 5.11.4 → 6.0.2
  • MockK 1.13.14 → 1.14.9
  • AssertJ 3.26.3 → 3.27.7
  • mannodermaus-junit5 1.11.2.0 → 2.0.1
• Add material-icons-core 1.7.8 (required for Material3 1.4.0+)
• Migrate to Compose BOM 2026.01.01 for centralized version management

AGP 9.0 Migration

• Remove kotlin-android plugin (AGP 9.0 provides built-in Kotlin support)
• Remove deprecated composeOptions block
• Move kotlin {} block to project level (outside android {})

Compose BOM Migration

• Replace explicit Compose dependency versions with Compose BOM 2026.01.01
• Ensures version compatibility across all Compose libraries
• BOM maps to identical versions (material-icons-core 1.7.8, material3 1.4.0, ui-tooling 1.10.2)

JUnit 5 → 6 Migration

JUnit 6 breaking changes verified as not affecting this project:

• ✅ Java 17 baseline - project uses JVM 21
• ✅ Kotlin 2.2 required - project uses Kotlin 2.3.0
• ✅ CSV parsing changes - @CsvSource/@CsvFileSource not used
• ✅ junit-platform-runner removed - not used
• ✅ JUnit Vintage deprecated - no JUnit 4 tests
• ✅ Maven Surefire 3.0.0+ - uses Gradle

Breaking Changes

• Example app minSdk updated from 21 to 23 (required by Compose Foundation 1.10.x)

Test plan

• Library builds successfully (./gradlew :library:assembleRelease)
• Library tests pass (./gradlew :library:test)
• Example app builds (./gradlew :exampleapp:assembleDebug)
• ktlint check passes
• Android lint passes