Ignore stale resume cursors and Claude placeholder thread IDs

- Do not pass `resumeCursor` when restarting a session after changing providers
- Treat synthetic Claude thread IDs (`claude-thread-*`) as unscoped during runtime ingestion
- Add tests covering provider-switch restart behavior and Claude turn lifecycle acceptance
8d23276affJulius Marminge committed on 2/28/2026, 5:35:57 AMparent2113000
4 files changedLine totals unavailable