useChat DX cleanup

@baleybots/react useChat is client-only again. Server-mode options and useGroupChat were removed — not deprecated behind flags.

What was removed

Removed	Replacement
useGroupChat	Client useChat for browser chat; hosted crew UI uses /api/chat + useCrewSessions
apiUrl, chatId, multiAgent, agents	Client useChat with model + optional storage; hosted crew chat via product /api/chat
loadHistory, isResuming	History via storage on client; server persistence in your route handler
pendingApproval, approveToolCall, rejectToolCall	pendingApprovals + respondToToolApprovals (batch)
SendStreamingOptions	Plain sendStreaming(content)
Primary messages rendering	segments + ChatTurns / ChatTurn

Hook messages still exists (derived via deriveUIMessages) for backward compatibility — do not build new UIs on it.

Migration

From useGroupChat / server-mode useChat

// Before — removed
import { useGroupChat } from '@baleybots/react';

const { messages, sendMessage } = useGroupChat({
  apiUrl: 'https://your-api.com/chat',
  chatId: 'conversation-123',
});

// After — client-side chat in the browser
import { useChat, ChatTurns, ChatTurn } from '@baleybots/react';
import { openai } from '@baleybots/core';

const { segments, sendStreaming } = useChat({
  model: openai('gpt-5.6-luna'),
  systemPrompt: 'You are a helpful assistant',
});

// Render
<ChatTurns segments={segments}>
  {(turn) => <ChatTurn key={turn.id} turn={turn} />}
</ChatTurns>

For multi-agent crew chat in the Baleybots product UI, connect to the host /api/chat endpoint and consume SSE with useCrewSessions — do not point useChat at a backend URL.

For your own server with tools, use createChatRoute from @baleybots/proxy-server (session HistoryStorage + bot-route mux) or createBotRoute for a single-shot Processable, with a fetch-based client — not removed useChat server mode. See Chat with Tools.

From messages to ChatTurns

// Before
{messages.map((msg) => (
  <div key={msg.id}>
    <b>{msg.role}:</b> {msg.content}
  </div>
))}

// After
import { useChat, ChatTurns, ChatTurn } from '@baleybots/react';

const { segments } = useChat({ model: 'openai|gpt-5.6-luna' });

<ChatTurns segments={segments}>
  {(turn) => <ChatTurn key={turn.id} turn={turn} />}
</ChatTurns>

From scalar approvals to batch approvals

// Before — removed
const { pendingApproval, approveToolCall, rejectToolCall } = useChat({ tools });

// After
const { pendingApprovals, respondToToolApprovals } = useChat({ tools });

if (pendingApprovals.length > 0) {
  respondToToolApprovals(
    pendingApprovals.map((p) => ({ approvalId: p.approvalId, approved: true })),
  );
}

Submit exactly one decision per entry in pendingApprovals before the turn resumes.

Legacy UIChatMessage[] consumers

If another hook or analytics layer still needs OpenAI-shaped rows:

import { deriveUIMessages } from '@baleybots/core';

const messages = deriveUIMessages(segments);

Key differences (summary)

Old pattern	New pattern
useGroupChat + apiUrl	Client useChat or host /api/chat
messages.map(...)	ChatTurns + ChatTurn
sendMessage	sendStreaming or send
pendingApproval / approveToolCall()	pendingApprovals / respondToToolApprovals([...])
multiAgent + agents	Crew UI / orchestration layer (out of scope for useChat)