feat(android): initial project setup with Gradle, AndroidManifest, and MainActivity

android-app/app/src/main/AndroidManifest.xml

@@ -0,0 +1,15 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="de.harheimertc">
+
+    <application
+        android:label="HarheimerTC"
+        android:icon="@mipmap/ic_launcher">
+        <activity android:name="de.harheimertc.MainActivity"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>

android-app/app/src/main/java/de/harheimertc/MainActivity.kt

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+package de.harheimertc
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.compose.material3.Text
+import androidx.compose.ui.tooling.preview.Preview
+
+class MainActivity : ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContent {
+            Text("HarheimerTC - App Scaffold")
+        }
+    }
+}
+
+@Preview
+fun PreviewMain() {
+    Text("Preview")
+}

android-app/app/src/main/res/values/colors.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <color name="primary_500">#ef4444</color>
+    <color name="primary_600">#dc2626</color>
+    <color name="accent_500">#71717a</color>
+</resources>