feat: add companion API and Android APK shell

apps/mobile/android/app/capacitor.build.gradle

@@ -0,0 +1,19 @@
+// DO NOT EDIT THIS FILE! IT IS GENERATED EACH TIME "capacitor update" IS RUN
+
+android {
+  compileOptions {
+      sourceCompatibility JavaVersion.VERSION_21
+      targetCompatibility JavaVersion.VERSION_21
+  }
+}
+
+apply from: "../capacitor-cordova-android-plugins/cordova.variables.gradle"
+dependencies {
+
+
+}
+
+
+if (hasProperty('postBuildExtras')) {
+  postBuildExtras()
+}