In-chat errors and automatic token refresh

This release displays Elements errors directly in the chat interface and adds automatic session token refresh before chat requests.

Show Elements errors inside the chat #1633 - Elements errors now appear directly in the chat conversation for easier debugging. (Author: @chase-crumbaugh)
Auto-refresh expired session tokens #1615 - Added JWT expiry detection with a 30-second buffer, deduplicates concurrent refresh calls via fetchQuery, and falls back to the stale token on failure. Refresh is automatic for non-static sessions and skipped during replays. (Author: @walker-tx)