fix: replay request SSE responses after disconnect

[he-yufeng]

Summary

• persist request-scoped SSE events even after closeSSEStream() detaches the active controller
• avoid throwing when the terminal response is safely stored for replay
• add a regression test that closes a POST SSE stream, completes the tool while disconnected, and replays the final response through Last-Event-ID

To verify

• pnpm --filter @modelcontextprotocol/node test -- streamableHttp.test.ts -t closeSSE
• pnpm --filter @modelcontextprotocol/server test -- streamableHttp.test.ts
• pnpm --filter @modelcontextprotocol/server typecheck
• pnpm --filter @modelcontextprotocol/node typecheck
• pnpm --filter @modelcontextprotocol/server lint
• pnpm --filter @modelcontextprotocol/node lint
• pnpm --filter @modelcontextprotocol/server build
• pnpm --filter @modelcontextprotocol/node build
• git diff --check

[changeset-bot]

⚠️ No Changeset found

Latest commit: 3b217a2

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

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

[pkg-pr-new]

Open in StackBlitz

@modelcontextprotocol/client

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/client@2207

@modelcontextprotocol/codemod

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/codemod@2207

@modelcontextprotocol/server

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/server@2207

@modelcontextprotocol/express

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/express@2207

@modelcontextprotocol/fastify

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/fastify@2207

@modelcontextprotocol/hono

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/hono@2207

@modelcontextprotocol/node

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/node@2207

commit: 3b217a2