Guard provider lifecycle updates to primary thread and active turn

- Ignore auxiliary/non-active turn completions for session lifecycle and checkpoints
- Restrict runtime thread/turn IDs to provider IDs in contracts
- Add regression tests and ADR for lifecycle ownership rules
872b907372Julius Marminge committed on 2/27/2026, 10:10:34 PM· committed by Julius Marmingeparent0b8e098
7 files changedLine totals unavailable