Upgrade Android SDK to 35

Also adapt the call to build-tools/35.0.0/aidl, which now requires an
import path (-I. for the current directory).

Otherwise, it fails with:

    ERROR: android/view/IRotationWatcher.aidl:23.1-10: directory ./ is not found in any of the import paths:
     -

Also upgrade AGP (8.7.1) and Gradle (8.9), required for SDK 35.

<https://developer.android.com/build/releases/gradle-plugin#updating-gradle>