Squash-merge of fusion/fn-5053 (7 commits including retry duplicates).
Drops stale conflict in packages/core/src/index.ts (FN-5053 branch
re-exported symbols that main already exports) and packages/core/src/store.ts
(branch had a stale, narrower updateTask signature; main is authoritative).
Manual CEO recovery after the trailerless-commit attribution bug
(now fixed by FN-5090 in 92be8225e) stranded this task in in-review.
Fusion-Task-Id: FN-5053
b9d4bd8c1b