chore: get Android project building (toolchain, deps, manifest, launcher icon)

- Fix dependency versions (Retrofit 2.11, OkHttp 4.12, Compose BOM)
- Add Material Components for the app theme
- Add --add-exports/--add-opens for kapt on JDK 21
- Remove deprecated manifest package attr; add INTERNET permission
- Add adaptive launcher icon

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -0,0 +1,4 @@
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@color/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>