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 `///`).

navigation_and_routing/lib/src/screens/authors.dart

@@ -12,7 +12,11 @@ class AuthorsScreen extends StatelessWidget {
   final String title;
   final ValueChanged<Author> onTap;
 
-  const AuthorsScreen({required this.onTap, this.title = 'Authors', super.key});
+  const AuthorsScreen({
+    required this.onTap,
+    this.title = 'Authors',
+    super.key,
+  });
 
   @override
   Widget build(BuildContext context) => Scaffold(

navigation_and_routing/lib/src/screens/book_details.dart

@@ -37,26 +37,24 @@ class BookDetailsScreen extends StatelessWidget {
               onPressed: () {
                 Navigator.of(context).push<void>(
                   MaterialPageRoute<void>(
-                    builder:
-                        (context) => AuthorDetailsScreen(
-                          author: book!.author,
-                          onBookTapped: (book) {
-                            GoRouter.of(
-                              context,
-                            ).go('/books/all/book/${book.id}');
-                          },
-                        ),
+                    builder: (context) => AuthorDetailsScreen(
+                      author: book!.author,
+                      onBookTapped: (book) {
+                        GoRouter.of(
+                          context,
+                        ).go('/books/all/book/${book.id}');
+                      },
+                    ),
                   ),
                 );
               },
             ),
             Link(
               uri: Uri.parse('/authors/author/${book!.author.id}'),
-              builder:
-                  (context, followLink) => TextButton(
-                    onPressed: followLink,
-                    child: const Text('View author (Link)'),
-                  ),
+              builder: (context, followLink) => TextButton(
+                onPressed: followLink,
+                child: const Text('View author (Link)'),
+              ),
             ),
           ],
         ),

navigation_and_routing/lib/src/screens/scaffold.dart

@@ -31,8 +31,14 @@ class BookstoreScaffold extends StatelessWidget {
         },
         destinations: const [
           AdaptiveScaffoldDestination(title: 'Books', icon: Icons.book),
-          AdaptiveScaffoldDestination(title: 'Authors', icon: Icons.person),
-          AdaptiveScaffoldDestination(title: 'Settings', icon: Icons.settings),
+          AdaptiveScaffoldDestination(
+            title: 'Authors',
+            icon: Icons.person,
+          ),
+          AdaptiveScaffoldDestination(
+            title: 'Settings',
+            icon: Icons.settings,
+          ),
         ],
       ),
     );

navigation_and_routing/lib/src/screens/settings.dart

@@ -26,7 +26,10 @@ class _SettingsScreenState extends State<SettingsScreen> {
             constraints: const BoxConstraints(maxWidth: 400),
             child: const Card(
               child: Padding(
-                padding: EdgeInsets.symmetric(vertical: 18, horizontal: 12),
+                padding: EdgeInsets.symmetric(
+                  vertical: 18,
+                  horizontal: 12,
+                ),
                 child: SettingsContent(),
               ),
             ),
@@ -44,7 +47,10 @@ class SettingsContent extends StatelessWidget {
   Widget build(BuildContext context) => Column(
     children: [
       ...[
-        Text('Settings', style: Theme.of(context).textTheme.headlineMedium),
+        Text(
+          'Settings',
+          style: Theme.of(context).textTheme.headlineMedium,
+        ),
         FilledButton(
           onPressed: () {
             BookstoreAuth.of(context).signOut();
@@ -54,11 +60,10 @@ class SettingsContent extends StatelessWidget {
         const Text('Example using the Link widget:'),
         Link(
           uri: Uri.parse('/books/all/book/0'),
-          builder:
-              (context, followLink) => TextButton(
-                onPressed: followLink,
-                child: const Text('/books/all/book/0'),
-              ),
+          builder: (context, followLink) => TextButton(
+            onPressed: followLink,
+            child: const Text('/books/all/book/0'),
+          ),
         ),
         const Text('Example using GoRouter.of(context).go():'),
         TextButton(
@@ -70,25 +75,23 @@ class SettingsContent extends StatelessWidget {
       ].map((w) => Padding(padding: const EdgeInsets.all(8), child: w)),
       const Text('Displays a dialog on the root Navigator:'),
       TextButton(
-        onPressed:
-            () => showDialog<String>(
-              context: context,
-              builder:
-                  (context) => AlertDialog(
-                    title: const Text('Alert!'),
-                    content: const Text('The alert description goes here.'),
-                    actions: [
-                      TextButton(
-                        onPressed: () => Navigator.pop(context, 'Cancel'),
-                        child: const Text('Cancel'),
-                      ),
-                      TextButton(
-                        onPressed: () => Navigator.pop(context, 'OK'),
-                        child: const Text('OK'),
-                      ),
-                    ],
-                  ),
-            ),
+        onPressed: () => showDialog<String>(
+          context: context,
+          builder: (context) => AlertDialog(
+            title: const Text('Alert!'),
+            content: const Text('The alert description goes here.'),
+            actions: [
+              TextButton(
+                onPressed: () => Navigator.pop(context, 'Cancel'),
+                child: const Text('Cancel'),
+              ),
+              TextButton(
+                onPressed: () => Navigator.pop(context, 'OK'),
+                child: const Text('OK'),
+              ),
+            ],
+          ),
+        ),
         child: const Text('Show Dialog'),
       ),
     ],