Pure advanceStreak (1-day grace none, milestone flags at 3/7/14/30),
persisted in the save blob; StreakNotifier advances on every finished
attempt; home screen flame chip and milestone snackbar. Fix flutter
create's camelCased iOS bundle id and underscored Android application
id to the agreed lowercase form before any store registration.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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