design(react): nothing can be imported from `@ic-reactor/react` in a React Server Component, not even the core classes it re-exports

[b3hr4d]

What happens

@ic-reactor/react has one entry, dist/index.js, which re-exports @ic-reactor/core and every hook module. A React Server Component that imports anything from it, including only ClientManager and Reactor, pulls in useSyncExternalStore, useEffect, useRef and useState, and the App Router build fails. Measured in examples/nextjs-app-router (Next 16, Turbopack) with one server-component page:

page imports	next build
defineReactor from @ic-reactor/react	fails: "You're importing a module that depends on useSyncExternalStore into a React Server Component module"
ClientManager, Reactor from @ic-reactor/react	fails: 6 errors, "depends on useEffect" / useRef / useState
ClientManager, Reactor from @ic-reactor/core (listed in package.json)	builds, exit 0

The README says the package "re-exports everything from @ic-reactor/core" so users "can import these from a single package", and until the docs fix in docs/react-readme-rsc-auth it said a server component may import Reactor / ClientManager from it.

Options

A. Docs only (done in docs/react-readme-rsc-auth). Server components import from @ic-reactor/core and list it as a dependency. No package change. Cost: React apps need a second runtime dependency for server code, and the "single package" promise has an exception.

B. A react-server export condition. Add "react-server": "./dist/server.js" to exports["."], where server.js re-exports @ic-reactor/core and nothing that imports a React hook. Next.js, and any bundler that honours the condition, resolves that entry in the server graph, so import { Reactor } from "@ic-reactor/react" works in a server component. Importing defineReactor or a hook there fails at build time with a missing-export error rather than a hook error. Types are unchanged (TypeScript does not read react-server). Needs pnpm verify:packages (publint/attw) and an App Router build check in CI.

C. "use client" on the hook modules. Marks the hooks as client references. Server imports of ClientManager would then compile, but a server component calling defineReactor or a hook would get a client-reference proxy and fail at runtime instead of at build time. This also changes how every bundler treats the package, so I would not choose it.

Recommendation

A now, which is already on a branch. Consider B if App Router users are a target audience: it is additive, keeps one import path, and turns a confusing hook error into a clear missing-export one. Not implemented, because it changes the published exports map.