feat(sdk-android): scaffold Android library module

AGP 8.11.0, Kotlin 2.1.21, minSdk 24, compileSdk 35, JDK 17
bytecode, no Compose dep. Uatu object exposes start/extract as
stubs; real implementation in tasks #6–8.

sdk/android/build.gradle.kts

@@ -0,0 +1,27 @@
+plugins {
+    id("com.android.library") version "8.11.0"
+    kotlin("android") version "2.1.21"
+}
+
+android {
+    namespace = "dev.uatu.sdk"
+    compileSdk = 35
+
+    defaultConfig {
+        minSdk = 24
+        consumerProguardFiles("consumer-rules.pro")
+    }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+
+    kotlinOptions {
+        jvmTarget = "17"
+    }
+}
+
+dependencies {
+    testImplementation("junit:junit:4.13.2")
+}