Add daily streak system and normalize bundle id to com.airkjw.blockseasons

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>

android/app/build.gradle.kts

@@ -20,8 +20,9 @@ android {
     }
 
     defaultConfig {
-        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
-        applicationId = "com.airkjw.block_seasons"
+        // Store-facing application id; the internal namespace keeps the
+        // generated package name.
+        applicationId = "com.airkjw.blockseasons"
         // You can update the following values to match your application needs.
         // For more information, see: https://flutter.dev/to/review-gradle-config.
         minSdk = flutter.minSdkVersion