fix: respect a registered message page size and accept ClientUser in useCreateChatClient

[oliverlaz]

🎯 Goal

Fix the SDK-side problems the v10 public-API audit found (listed in ai-docs/v10-breaking-changes.md §16 in #3870), so they ship fixed instead of documented as limitations.

The docs PR #3870 already drops these known-issue notes from ai-docs/v10-breaking-changes.md and ai-docs/ai-migration-v9-to-v10.md (§13.1, §16.1, §R.5), so it assumes this PR lands first or together with it. This PR is code only.

Stacked on #3869 (Ivan's stack: #3866 → #3867 → #3868 → #3869). The branch is rebased onto refactor/stop-creating-sdk-paginator; until the PR base is moved there, the diff also shows that stack's commits.

🛠 Implementation details

• <Channel> overrode a registered page size. On every mount it ran channel.messagePaginator.pageSize = 25 (now in useChannelLifecycle, after refactor: clean up channel lifecycle #3868). That setter is a runtime updateConfig patch, which outranks every declarative layer, so a client.config.set({ channel: { messagePaginator: { pageSize } } }) registration (the migration guide's advice) never took effect. useChannelLifecycle now applies the 25-message default only when no pageSize is registered under channel.messagePaginator or the general messagePaginator key, the two places the paginator resolves it from.
• useCreateChatClient({ userData }) rejected { id, name, image }. It was typed OwnUserResponse | UserResponse, which require server-owned fields (role, created_at, …) in stream-chat v10. It is now ClientUser, exactly what client.connectUser accepts. The as UserResponse casts in ExpoChatGPTSample and ExpoMessaging are gone (ExpoMessaging keeps as ClientUser only to narrow away null).
• AGENTS.md said the main entry must never reach @stream-io/state-store, but the state-store/ stores and Poll contexts import it at runtime. The rule now matches package/bin/validate-entry-isolation.js (@stream-io/state-store and lodash are shared; only react-syntax-highlighter, @khanacademy/simple-markdown, zod, victory-native and Skia are AI-only), and the script path is corrected.

🎨 UI Changes

None.

🧪 Testing

• Channel.test.tsx (still passes on the rebased base) → "message page size": default 25 with nothing registered, and a registered channel.messagePaginator.pageSize / messagePaginator.pageSize is kept after mount. The two registration cases fail with the guard removed.
• New useCreateChatClient.userData.test.ts: a type-level assertion that the hook's userData and connectUser's parameter are mutually assignable (it fails test:typecheck under the old typing), plus a runtime check that a { id, name, image } user is passed to connectUser.
• After the rebase onto refactor: stop creating sdk paginator #3869: yarn lint, cd package && yarn test:typecheck, and the Channel and useCreateChatClient suites pass. Before the rebase, locally green: yarn build, yarn lint, cd package && yarn test:typecheck, yarn typecheck (covers the example apps without the casts), yarn test:unit (2200 passed).

☑️ Checklist

• I have signed the Stream CLA (required)
• PR targets the develop branch (targets V10: v10 release fix)
• Documentation is updated (AGENTS.md; migration docs in docs: v10 breaking-changes inventory and v9→v10 ledger audit #3870)
• New code is tested in main example apps, including all possible scenarios
  • SampleApp iOS and Android
  • Expo iOS and Android

[Stream-SDK-Bot]

SDK Size

title	develop	branch	diff	status
js_bundle_size	2036 KB	2018 KB	-18354 B	🚀
ai_components_size	130 KB	130 KB	0 B	🟢