- Hoist todo to first-class widget (shadcn checkboxes, brand colors, no
tool-accordion). Header derives label from active task; non-active rows fade.
- Replace raw JSON dumps with structured key/value summaries via
formatToolResultSummary; nested error extraction for clearer failures.
- Fix loaded-session grouping: stitch interleaved assistant/tool iterations
into one bubble instead of orphaned synthetic messages.
- Stable tool/thinking timers via keyed registry so unmount/scroll doesn't
reset elapsed counts; gate "running" on real live thread state.
- Reorganize chat-only assistant-ui components under components/chat/.