Bump ai to 38734ffec837c55ecb8c657384c5db06d46ebd53

Changes:
```
> git log --format="%C(auto) %h %s" d0b89cf..38734ff
 https://dart.googlesource.com/ai.git/+/38734ff Migrate to the connected app service (208)
 https://dart.googlesource.com/ai.git/+/b7d438b disable the screenshots tool by default (210)
 https://dart.googlesource.com/ai.git/+/c230aaa expose public arg_parser.dart library (209)
 https://dart.googlesource.com/ai.git/+/7d7e7f9 Fix `--log-file` option so it doesn't crash the server. (207)
 https://dart.googlesource.com/ai.git/+/2676dec Add documentation for setting up the MCP server in popular clients (201)
 https://dart.googlesource.com/ai.git/+/6861301 Pin the SDK git ref and add caching on github actions (205)
 https://dart.googlesource.com/ai.git/+/6b84c96 update MCPClient.connectStdioServer to operate on streams and sinks (204)
 https://dart.googlesource.com/ai.git/+/04eee07 Fix readme link (203)
 https://dart.googlesource.com/ai.git/+/8aa3a8b add a github workflow for mcp_examples/ (191)
 https://dart.googlesource.com/ai.git/+/1af73bc auto validate tool arguments, improve validation messages (200)
 https://dart.googlesource.com/ai.git/+/0b22b67 Update to new MCP spec version (193)
 https://dart.googlesource.com/ai.git/+/a74efc3 Update `simple_client.dart` for updated `hello_world` tool name (194)

```

Diff: https://dart.googlesource.com/ai.git/+/d0b89cffe58d208ba7070c784ed855820997b004..38734ffec837c55ecb8c657384c5db06d46ebd53/
Change-Id: I014869b4da5b5ba97fecb83a19f6cdb1c02be5f7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/437920
Commit-Queue: Jake Macdonald <[email protected]>
Reviewed-by: Kenzie Davisson <[email protected]>
Auto-Submit: Jake Macdonald <[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": "d0b89cffe58d208ba7070c784ed855820997b004",
+  "ai_rev": "38734ffec837c55ecb8c657384c5db06d46ebd53",
   "core_rev": "b59ecf4ceebe6153e1c0166b7c9a7fdd9458a89d",
   "dartdoc_rev": "f1fe17752b1193ad52d69271ceb686cc3e4712b0",
   "ecosystem_rev": "d5233c6dd0767cffa5742e32c4bc7c230c9c4b12",

pkg/dartdev/test/commands/mcp_server_test.dart

@@ -15,11 +15,13 @@ void main() {
           () async {
         final client = TestMCPClient();
         addTearDown(client.shutdown);
-        final serverConnection =
-            await client.connectStdioServer(Platform.resolvedExecutable, [
+        final process = await Process.start(Platform.resolvedExecutable, [
           'mcp-server',
           if (withExperiment) '--experimental-mcp-server',
         ]);
+        final serverConnection = client.connectStdioServer(
+            process.stdin, process.stdout,
+            onDone: process.kill);
         final initializeResult = await serverConnection.initialize(
             InitializeRequest(
                 protocolVersion: ProtocolVersion.latestSupported,