create PackageManifest.kt and get test working

api/build.gradle.kts

@@ -1,9 +1,32 @@
 plugins {
-    id("buildsrc.convention.kotlin-jvm")
+    kotlin("multiplatform")
     alias(libs.plugins.kotlinPluginSerialization)
 }
+kotlin {
+    jvm()
+    val nativeTarget = if(System.getProperty("os.arch") == "aarch64") {
+        linuxArm64("native")
+    } else {
+        linuxX64("native")
+    }
+    nativeTarget.binaries {
+        sharedLib {
+            baseName = "planterette"
+        }
+    }
+    sourceSets {
+        commonMain.dependencies {
+            implementation(libs.bundles.kotlinxEcosystem)
+        }
+        commonTest.dependencies {
+            implementation(libs.bundles.kotlinxEcosystem)
+            implementation(kotlin("test"))
+        }
+        jvmMain.dependencies {
 
-dependencies {
-    implementation(libs.bundles.kotlinxEcosystem)
-    testImplementation(kotlin("test"))
-}
+        }
+        jvmTest.dependencies {
+
+        }
+    }
+}