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/data/repositories/activity/activity_repository_local.dart

@@ -18,10 +18,9 @@ class ActivityRepositoryLocal implements ActivityRepository {
   @override
   Future<Result<List<Activity>>> getByDestination(String ref) async {
     try {
-      final activities =
-          (await _localDataService.getActivities())
-              .where((activity) => activity.destinationRef == ref)
-              .toList();
+      final activities = (await _localDataService.getActivities())
+          .where((activity) => activity.destinationRef == ref)
+          .toList();
 
       return Result.ok(activities);
     } on Exception catch (error) {