Respect provider model-switch limits and canonical runtime events

- Add provider capability plumbing for `sessionModelSwitch` and use it in session/turn routing
- Keep Cursor sessions stable when in-session model switching is unsupported
- Ingest canonical runtime events (`content.delta`, `item.*`, `request.*`) with legacy-shape compatibility
17e6cad479Julius Marminge committed on 3/6/2026, 7:00:41 AM· committed by Julius Marmingeparentfeff866
20 files changedLine totals unavailable