build: AGP 8.13.2 with R8 9.1.43 so D8 can read Kotlin 2.4 metadata

The Kotlin version moved to 2.4.10 while AGP stayed on 8.12.1, whose bundled
R8 (8.12.14) predates Kotlin 2.4 metadata. Every dex step then logs
"An error occurred when parsing kotlin metadata" once per Kotlin stdlib class,
about a thousand lines per build. Kotlin 2.4 needs R8 9.1.29 or newer, which
no 8.x AGP bundles, so R8 is pinned on the buildscript classpath the way the
AGP/Kotlin compatibility docs describe, and AGP moves to the last 8.x release.
Both are overridable per project like the existing versions.

Author: edusperoni

test-app/build.gradle

@@ -134,15 +134,18 @@ version of the {N} CLI install a previous version of the runtime package - 'tns
 
     def computeKotlinVersion = { -> project.hasProperty("kotlinVersion") ? kotlinVersion : "${ns_default_kotlin_version}" }
     def computeBuildToolsVersion = { -> project.hasProperty("androidBuildToolsVersion") ? androidBuildToolsVersion : "${NS_DEFAULT_ANDROID_BUILD_TOOLS_VERSION}" }
+    def computeR8Version = { -> project.hasProperty("r8Version") ? r8Version : "${NS_DEFAULT_R8_VERSION}" }
     def kotlinVersion = computeKotlinVersion()
     def androidBuildToolsVersion = computeBuildToolsVersion()
+    def r8Version = computeR8Version()
 
     repositories {
         google()
         mavenCentral()
     }
     dependencies {
         classpath "com.android.tools.build:gradle:$androidBuildToolsVersion"
+        classpath "com.android.tools:r8:$r8Version"
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
         classpath "org.apache.groovy:groovy-all:4.0.21"
     }

test-app/gradle.properties

@@ -22,7 +22,9 @@ android.useAndroidX=true
 NS_DEFAULT_BUILD_TOOLS_VERSION=35.0.0
 NS_DEFAULT_COMPILE_SDK_VERSION=35
 NS_DEFAULT_MIN_SDK_VERSION=21
-NS_DEFAULT_ANDROID_BUILD_TOOLS_VERSION=8.12.1
+NS_DEFAULT_ANDROID_BUILD_TOOLS_VERSION=8.13.2
+# R8 8.x cannot read Kotlin 2.4 metadata (needs 9.1.29+), so the AGP-bundled R8 is overridden.
+NS_DEFAULT_R8_VERSION=9.1.43
 
 ns_default_androidx_appcompat_version = 1.7.0
 ns_default_androidx_exifinterface_version = 1.3.7