Centralize all plugin + dependency versions in gradle/libs.versions.toml (the
modern Gradle standard) and switch the root + app build scripts to the generated
libs.* / alias(libs.plugins.*) accessors. No version changes — a 1:1 migration of
the 57 hardcoded coordinates. Full assembleDebug + unit suite green.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>