Scaffold native Android build and enforce Rust boundaries (#89)

android/rust-bridge/build.gradle.kts

@@ -0,0 +1,32 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
+plugins {
+    alias(libs.plugins.android.library)
+}
+
+android {
+    namespace = "de.rfc1437.ironstorage.rustbridge"
+    compileSdk = libs.versions.compileSdk.get().toInt()
+    ndkVersion = libs.versions.ndk.get()
+    defaultConfig {
+        minSdk = libs.versions.minSdk.get().toInt()
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+    defaultConfig { consumerProguardFiles("consumer-rules.pro") }
+    lint {
+        abortOnError = true
+        warningsAsErrors = true
+    }
+}
+
+kotlin {
+    jvmToolchain(25)
+    compilerOptions { jvmTarget.set(JvmTarget.JVM_17) }
+}
+
+dependencies {
+    testImplementation(libs.junit)
+}