fix(server): close stdio transport on stdin close

[harshmathurx]

Summary

• close StdioServerTransport when stdin emits close or end
• remove stdin lifecycle listeners during transport close
• add regression coverage for both stdin close paths

Fixes #2002.

Test Plan

• npx -y pnpm@10.26.1 --filter @modelcontextprotocol/server test -- packages/server/test/server/stdio.test.ts
• npx -y pnpm@10.26.1 --filter @modelcontextprotocol/server lint

[changeset-bot]

🦋 Changeset detected

Latest commit: 98f7d00

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@modelcontextprotocol/server	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[pkg-pr-new]

Open in StackBlitz

@modelcontextprotocol/client

npm i https://pkg.pr.new/@modelcontextprotocol/client@2473

@modelcontextprotocol/codemod

npm i https://pkg.pr.new/@modelcontextprotocol/codemod@2473

@modelcontextprotocol/core

npm i https://pkg.pr.new/@modelcontextprotocol/core@2473

@modelcontextprotocol/server

npm i https://pkg.pr.new/@modelcontextprotocol/server@2473

@modelcontextprotocol/server-legacy

npm i https://pkg.pr.new/@modelcontextprotocol/server-legacy@2473

@modelcontextprotocol/express

npm i https://pkg.pr.new/@modelcontextprotocol/express@2473

@modelcontextprotocol/fastify

npm i https://pkg.pr.new/@modelcontextprotocol/fastify@2473

@modelcontextprotocol/hono

npm i https://pkg.pr.new/@modelcontextprotocol/hono@2473

@modelcontextprotocol/node

npm i https://pkg.pr.new/@modelcontextprotocol/node@2473

commit: 98f7d00

[harshmathurx]

Pushed a small test-fixture follow-up after the Node 22 CI failure.

The failing job crashed because serverThatHangs.ts can receive SIGTERM after the stdio transport has already closed, then its late sendLoggingMessage() rejection escapes the signal handler. The fixture now ignores that expected late logging failure so the test keeps exercising process cleanup instead of crashing during teardown.

Local verification:

• corepack pnpm --dir test/integration test -- processCleanup.test.ts (ran the integration suite; 18 files / 353 tests passed)
• git diff --check

[harshmathurx]

@jspahrsummers gentle maintainer ping on this one. I pushed a follow-up for the Node 22 teardown failure and revalidated the targeted integration test locally. Most checks are green; the remaining failing test (20) looked unrelated to the transport fix path when I last checked. If you’d prefer I refresh/rebase the branch against current main before review, happy to do that. Otherwise would appreciate a look when you have a moment.