Lagrange v1.5.3-issue-181-debug-1

Feature

• Added a default-on global option to show the Android navigation bar while reading EPUB, PDF, and comic formats; audiobook playback is unchanged.
• When the navigation bar is visible, the EPUB reading viewport accounts for its bottom inset so the progress row and reader menus stay above it.

Validation

• The full JVM unit-test suite, Android-test Kotlin compilation, Android lint, and debug APK assembly passed for the issue implementation; the pull-request build-and-test workflow passed.
• The user confirmed the EPUB inset behavior works on-device.
• This prerelease provides the signed combined APK Lagrange-1.5.3-issue-181-debug-1.apk as the default download, with architecture-specific APK alternatives attached by the release workflow.