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 `///`).

add_to_app/plugin/flutter_module_using_plugin/lib/cell.dart

@@ -23,7 +23,12 @@ class Cell extends StatefulWidget {
 
 class _CellState extends State<Cell> with WidgetsBindingObserver {
   static const double gravity = 9.81;
-  static final AccelerometerEvent defaultPosition = AccelerometerEvent(0, 0, 0);
+  static final AccelerometerEvent defaultPosition = AccelerometerEvent(
+    0,
+    0,
+    0,
+    DateTime.now(),
+  );
 
   int cellNumber = 0;
   Random? _random;
@@ -82,7 +87,10 @@ class _CellState extends State<Cell> with WidgetsBindingObserver {
           builder: (context) {
             return Card(
               // Mimic the platform Material look.
-              margin: const EdgeInsets.symmetric(horizontal: 36, vertical: 24),
+              margin: const EdgeInsets.symmetric(
+                horizontal: 36,
+                vertical: 24,
+              ),
               shape: RoundedRectangleBorder(
                 borderRadius: BorderRadius.circular(16),
               ),
@@ -112,10 +120,9 @@ class _CellState extends State<Cell> with WidgetsBindingObserver {
                       child: StreamBuilder<AccelerometerEvent>(
                         // Don't continuously rebuild for nothing when the
                         // cell isn't visible.
-                        stream:
-                            appLifecycleState == AppLifecycleState.resumed
-                                ? accelerometerEventStream()
-                                : Stream.value(defaultPosition),
+                        stream: appLifecycleState == AppLifecycleState.resumed
+                            ? accelerometerEventStream()
+                            : Stream.value(defaultPosition),
                         initialData: defaultPosition,
                         builder: (context, snapshot) {
                           final data = snapshot.data;
@@ -125,11 +132,14 @@ class _CellState extends State<Cell> with WidgetsBindingObserver {
                           return Transform(
                             // Figure out the phone's orientation relative
                             // to gravity's direction. Ignore the z vector.
-                            transform: Matrix4.rotationX(
-                              data.y / gravity * pi / 2,
-                            )..multiply(
-                              Matrix4.rotationY(data.x / gravity * pi / 2),
-                            ),
+                            transform:
+                                Matrix4.rotationX(
+                                  data.y / gravity * pi / 2,
+                                )..multiply(
+                                  Matrix4.rotationY(
+                                    data.x / gravity * pi / 2,
+                                  ),
+                                ),
                             alignment: Alignment.center,
                             child: const FlutterLogo(size: 72),
                           );

add_to_app/plugin/flutter_module_using_plugin/pubspec.yaml

@@ -1,17 +1,17 @@
 name: flutter_module_using_plugin
 description: An example Flutter module that uses a plugin.
-
 version: 1.0.0+1
+resolution: workspace
 
 environment:
-  sdk: ^3.7.0-0
+  sdk: ^3.9.0-0
 
 dependencies:
   flutter:
     sdk: flutter
   provider: ^6.0.2
   url_launcher: ^6.0.20
-  sensors_plus: ^5.0.1
+  sensors_plus: ^6.1.1
 
 dev_dependencies:
   analysis_defaults: