init: android project scaffold (Phase 28.1)

- Kotlin DSL build with version catalog (AGP 8.7, Kotlin 2.1, Compose BOM 2025.01)
- app module: Compose + Material 3, dark theme, network security config
- DualNetworkTestScreen — Phase 28.1 gate screen (buttons wired in 28.1.2)
- YarisApp, MainActivity, YarisOBDTheme
- ProGuard rules for Retrofit/OkHttp/Kotlinx Serialization/Coil/MapLibre/Room
- cleartext allowed for 10.42.0.1 + yaris.local
- gradle wrapper properties (needs Android Studio to generate wrapper jar)

android/app/src/main/res/values/strings.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="app_name">yaris-obd</string>
+</resources>

android/app/src/main/res/values/themes.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <style name="Theme.YarisOBD" parent="android:Theme.Material.NoActionBar">
+        <item name="android:statusBarColor">@android:color/black</item>
+        <item name="android:navigationBarColor">@android:color/black</item>
+    </style>
+</resources>

android/app/src/main/res/xml/network_security_config.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<network-security-config>
+    <!-- Allow cleartext to Pi hotspot (10.42.0.1) — local-only, no internet -->
+    <domain-config cleartextTrafficPermitted="true">
+        <domain includeSubdomains="false">10.42.0.1</domain>
+        <domain includeSubdomains="false">yaris.local</domain>
+    </domain-config>
+</network-security-config>