Dart 3.9 / Flutter 3.35 [first LLM release] (#2714)

I got carried away with Gemini and basically rewrote CI and the release
process for the new LLM reality. This work was largely completed by
Gemini.

- Bump all SDK versions to the current beta (3.9.0-0)
- Run `flutter channel beta`
- Wrote `ci_script.dart` to replace the bash scripts
- Converted repository to pub workspace #2499 
- Added llm.md and release.md
- Added redirect for deprecated Samples Index

## Pre-launch Checklist

- [x] I read the [Flutter Style Guide] _recently_, and have followed its
advice.
- [x] I signed the [CLA].
- [x] I read the [Contributors Guide].
- [x] I have added sample code updates to the [changelog].
- [x] I updated/added relevant documentation (doc comments with `///`).

compass_app/app/lib/domain/use_cases/booking/booking_create_use_case.dart

@@ -63,12 +63,9 @@ class BookingCreateUseCase {
         return Result.error(activitiesResult.error);
       case Ok<List<Activity>>():
     }
-    final activities =
-        activitiesResult.value
-            .where(
-              (activity) => itineraryConfig.activities.contains(activity.ref),
-            )
-            .toList();
+    final activities = activitiesResult.value
+        .where((activity) => itineraryConfig.activities.contains(activity.ref))
+        .toList();
     _log.fine('Activities loaded (${activities.length})');
 
     // Check if dates are set