The "copy chat" button serialized `messageRows` (persisted rows loaded via
`useAiChatMessagesQuery`), which were incomplete in two ways, so the exported
Markdown dropped messages (e.g. "Messages: 2" for a multi-turn chat).
- Exhaust pagination: `useAiChatMessagesQuery` is a useInfiniteQuery that only
ever loaded the first page (server page size 50, oldest-first), silently
truncating longer chats. Add an effect that calls `fetchNextPage()` until
`hasNextPage` is false. Guard on `isFetchNextPageError` so a failed page fetch
does not loop on the app's global `retry: false`.
- Re-sync after each turn: `onTurnFinished` invalidated only the chat-list
query, never the per-chat messages query, so `messageRows` went stale during
a live session. Also invalidate `AI_CHAT_MESSAGES_RQ_KEY(activeChatId)` so the
export and token counters reflect the just-finished turn.
- Avoid tearing down the live thread: a render-phase latch (`historyLoadedKeyRef`)
keeps the history loader gating the FIRST mount only, so the post-turn
background refetch (which can transiently flip `hasNextPage` for a chat whose
message count is an exact multiple of the page size) no longer unmounts the
open thread and loses its in-progress useChat state.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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