piker/ai/prompt-io/20261106T185628Z_495c0915_215e9b_prompt_io.raw.md

git diff HEAD~1..HEAD -- piker/tsp/_history.py

git diff HEAD~1..HEAD -- tests/test_history_backfill.py

Partial backport of the NoData/DataUnavailable catch from 0846cbd4a4 into maybe_fill_null_segments(). The existing gap fallback remains in use. A new parametrized regression uses real null detection and verifies that a sibling in the same nursery survives the failed repair.

Both new cases failed before the catch. The focused history suites passed after it: 17 passed. This does not qualify live overlap or fix IB reset churn or the separate Tractor completion-callback assertion.