🚰 refactor: Move the Pure Stream Code into the @librechat/chat Core

[berry-13]

Summary

The stream code that turns server frames into message content is pure TypeScript, yet it lives in client/src/hooks/SSE, so another host cannot reuse it and nothing stops it from picking up app imports. This is link 5 of the @librechat/chat stack: the step appliers (steps/*), normalizeFrame (transport/frames.ts) and the SSE transport (transport/sse.ts) move with git mv into the package core, together with their four specs, and the client imports them from @librechat/chat. This is the first link where the client depends on the package, so the client build, its jest mapping, the lockfile and the CI jobs that typecheck, test or build the client now build or download the package's dist; the Dockerfiles already build it before the client.

The content applier read two ask-user-question predicates from ~/utils/approval. They move to core/ask.ts with the answered-actions set they read, and utils/approval.ts re-exports them, so its consumers are unchanged. Behavior is unchanged: the moved files differ only in that import and one return type the package's isolatedDeclarations requires.

Open PRs #16508 (steps/content.ts, steps/tools.ts, steps.spec.ts) and #16092 (useStepHandler.ts imports) will need to follow the rename to packages/chat/src/core.

Type of change

• Refactor
• Tests / tooling / CI

Testing

Tested environments/configuration:

• Node 24, npm ci from the public registry, full turbo build including the client

Automated tests:

• packages/chat: tsc --noEmit clean, jest 88 of 88 under the node environment, including the moved frames, sse, steps and transport specs unchanged
• client: src/hooks/SSE 12 suites, 423 tests (useStepHandler, useResumableSSE, useResumeOnLoad among them), resolving @librechat/chat from packages/chat/dist; related tests of utils/approval.ts and ChatTransportContext.tsx, 549 suites; tsc --noEmit clean
• Added a scenario to chat-package.spec.ts that resolves @librechat/chat from the client workspace to dist/index.cjs and loads the stream API through CJS and ESM with every UI module blocked; the step-reducer, tool-steps and chat-facade-transport mock scenarios stream through the built client
• npm run build: the client bundle builds against the package dist

Screenshots / recordings

No user-facing change.

Risk / compatibility

sse.js becomes a dependency of the package; the client keeps its own entry because useSubagentActivityStream imports it directly. The package's lint block gains the _-prefix convention for unused names that the moved specs used under the client config. The lockfile only records the two new dependency edges.

Checklist

• I reviewed my own changes
• Relevant tests have been added or updated
• Existing relevant tests pass
• The change does not introduce new warnings or errors
• Required dependency changes have been merged/published
• Required documentation PR: N/A

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[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-11T16:13:54.004431Z	2ed7c6c	Draft marked ready
🔒 Security Review	✅ Completed 2026-10-11T16:10:34.949950Z	2ed7c6c	Draft marked ready

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