use createArgParser from package:dart_mcp_server to support all args automatically

Bump ai to 64dfa7f138aa4d9bcc06e807858136b7d4d296d3

Changes:
```
> git log --format="%C(auto) %h %s" 38734ff..64dfa7f
 https://dart.googlesource.com/ai.git/+/64dfa7f move static argParser variable to a createArgParser function (212)
 https://dart.googlesource.com/ai.git/+/a5aa053 Bump actions/cache from 4.2.2 to 4.2.3 in the github-actions group (211)

```

Diff: https://dart.googlesource.com/ai.git/+/38734ffec837c55ecb8c657384c5db06d46ebd53..64dfa7f138aa4d9bcc06e807858136b7d4d296d3/
Change-Id: Ibbf884d4eaaaf07664567fa2efb655ed9e90f9c3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/438280
Commit-Queue: Jake Macdonald <[email protected]>
Auto-Submit: Jake Macdonald <[email protected]>
Reviewed-by: Ivan Inozemtsev <[email protected]>
Reviewed-by: Alexander Markov <[email protected]>

Author: jakemac53

DEPS

@@ -131,7 +131,7 @@ vars = {
   ### /third_party/pkg dependencies
   # 'tools/rev_sdk_deps.dart' will rev pkg dependencies to their latest; put an
   # EOL comment after a dependency to instead pin at the current revision.
-  "ai_rev": "38734ffec837c55ecb8c657384c5db06d46ebd53",
+  "ai_rev": "64dfa7f138aa4d9bcc06e807858136b7d4d296d3",
   "core_rev": "b59ecf4ceebe6153e1c0166b7c9a7fdd9458a89d",
   "dartdoc_rev": "f1fe17752b1193ad52d69271ceb686cc3e4712b0",
   "ecosystem_rev": "d5233c6dd0767cffa5742e32c4bc7c230c9c4b12",

pkg/dartdev/lib/src/commands/dart_mcp_server.dart

@@ -4,6 +4,10 @@
 
 import 'dart:async';
 
+import 'package:args/args.dart';
+import 'package:dart_mcp_server/arg_parser.dart' as dart_mcp_server;
+import 'package:dartdev/src/utils.dart';
+
 import '../core.dart';
 import '../sdk.dart';
 import '../vm_interop_handler.dart';
@@ -14,44 +18,43 @@ class DartMCPServerCommand extends DartdevCommand {
   static const String cmdDescription = '''
 A stdio based Model Context Protocol (MCP) server to aid in Dart and Flutter development.''';
 
-  static const _forceRootsFallbackFlag = 'force-roots-fallback';
   static const _experimentFlag = 'experimental-mcp-server';
 
+  @override
+  ArgParser createArgParser() => dart_mcp_server.createArgParser(
+      usageLineLength: dartdevUsageLineLength, includeHelp: false);
+
   DartMCPServerCommand({bool verbose = false})
       : super(cmdName, cmdDescription, verbose, hidden: true) {
-    argParser
-      ..addFlag(
-        _forceRootsFallbackFlag,
-        negatable: true,
+    argParser.addFlag(_experimentFlag,
+        // This flag is no longer required but we are leaving it in for
+        // backwards compatibility.
+        hide: true,
         defaultsTo: false,
-        help:
-            'Forces a behavior for project roots which uses MCP tools instead '
-            'of the native MCP roots. This can be helpful for clients like '
-            'Cursor which claim to have roots support but do not actually '
-            'support it.',
-      )
-      ..addFlag(_experimentFlag,
-          // This flag is no longer required but we are leaving it in for
-          // backwards compatibility.
-          hide: true,
-          defaultsTo: false,
-          help: 'A required flag in order to use this command. Passing this '
-              'flag is an acknowledgement that you understand it is an '
-              'experimental feature with no stability guarantees.');
+        help: 'A required flag in order to use this command. Passing this '
+            'flag is an acknowledgement that you understand it is an '
+            'experimental feature with no stability guarantees.');
   }
 
   @override
   CommandCategory get commandCategory => CommandCategory.tools;
 
   @override
   Future<int> run() async {
-    final args = argResults!;
+    final parsedArgs = argResults!;
+
+    // Strip out the experiment flag before forwarding on the args, this flag
+    // isn't supported by the actual binary.
+    final forwardedArgs = argResults!.arguments.toList();
+    if (parsedArgs.wasParsed(_experimentFlag)) {
+      forwardedArgs.removeWhere((arg) => arg.endsWith(_experimentFlag));
+    }
     try {
       VmInteropHandler.run(
         sdk.dartAotRuntime,
         [
           sdk.dartMCPServerAotSnapshot,
-          if (args.flag(_forceRootsFallbackFlag)) '--$_forceRootsFallbackFlag'
+          ...forwardedArgs,
         ],
         useExecProcess: true,
       );

pkg/dartdev/pubspec.yaml

@@ -18,6 +18,7 @@ dependencies:
   code_assets: any
   collection: any
   dart2native: any
+  dart_mcp_server: any
   dart_style: any
   dartdoc: any
   data_assets: any