The Gemma model requires Kaggle login/licence so direct HTTP download is
not possible. Replaces the download screen with adb transfer instructions,
a Scan button that checks the file on disk, and a Continue without AI bypass.
Also renames the Android package from com.example.dailyou to
net.stefwill.dailyou (build.gradle.kts, MainActivity.kt path + declaration)
and adds *.bin to .gitignore to keep model files out of the repo.
Adds a one-time download flow for the on-device Gemma 2B model (~1.1 GB)
with a progress bar, partial-download cleanup, and automatic navigation
to the app shell once the file is verified. App.dart now gates on
modelPresentProvider instead of onboarding state.