#164 Stage B requires exposing whether cancellation was observed at the
turn-result level. This commit adds the infrastructure field:
Changes:
- TurnResult.cancel_observed: bool = False (query_engine.py)
- _build_timeout_result() accepts cancel_observed parameter (runtime.py)
- Two timeout paths now pass cancel_event.is_set() to signal observation (runtime.py)
- bootstrap command includes cancel_observed in turn JSON (main.py)
- SCHEMAS.md documents Turn Result Fields with cancel_observed contract
Usage:
When a turn timeout occurs, cancel_observed=true indicates that the
engine observed the cancellation event being set. This allows callers
to distinguish:
- timeout with no cancel → infrastructure/network stall
- timeout with cancel observed → cooperative cancellation was triggered
Backward compat:
- Existing TurnResult construction without cancel_observed defaults to False
- bootstrap JSON output still validates per SCHEMAS.md (new field is always present)
Test results: 182 passing, 3 skipped, zero regression.
Related: #161 (wall-clock timeout), #164 (cancellation observability protocol)
ROADMAP continues #164 with Stage C (test coverage for cancellation + turn envelope).
97c4b130dc