Prerelease build for issue #168.
Audiobook playback speed now uses an adjustable overlay from 0.25x through 3.00x with 0.05x and 0.10x controls, immediate persistence, and fixed two-decimal labels.
This is a debug APK for reporter testing, not a signed production release. It is arm64-v8a-only. The app update detector does not surface prereleases automatically; use the direct APK asset link.
Automated verification: 728 JVM tests passed, Kotlin and Android-test compilation passed, lint passed with 0 errors, and debug/Android-test APK assembly passed. No connected device was available for assistant-side device validation.