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/booking/booking_repository_local.dart

@@ -68,11 +68,10 @@ class BookingRepositoryLocal implements BookingRepository {
     // create a default booking the first time
     if (_bookings.isEmpty) {
       final destination = (await _localDataService.getDestinations()).first;
-      final activities =
-          (await _localDataService.getActivities())
-              .where((activity) => activity.destinationRef == destination.ref)
-              .take(4)
-              .toList();
+      final activities = (await _localDataService.getActivities())
+          .where((activity) => activity.destinationRef == destination.ref)
+          .take(4)
+          .toList();
 
       _bookings.add(
         Booking(

compass_app/app/lib/data/repositories/booking/booking_repository_remote.dart

@@ -27,8 +27,9 @@ class BookingRepositoryRemote implements BookingRepository {
         endDate: booking.endDate,
         name: '${booking.destination.name}, ${booking.destination.continent}',
         destinationRef: booking.destination.ref,
-        activitiesRef:
-            booking.activity.map((activity) => activity.ref).toList(),
+        activitiesRef: booking.activity
+            .map((activity) => activity.ref)
+            .toList(),
       );
       return _apiClient.postBooking(bookingApiModel);
     } on Exception catch (e) {
@@ -72,10 +73,9 @@ class BookingRepositoryRemote implements BookingRepository {
           return Result.error(resultActivities.error);
         case Ok<List<Activity>>():
       }
-      final activities =
-          resultActivities.value
-              .where((activity) => booking.activitiesRef.contains(activity.ref))
-              .toList();
+      final activities = resultActivities.value
+          .where((activity) => booking.activitiesRef.contains(activity.ref))
+          .toList();
 
       return Result.ok(
         Booking(