Reconcile every accepted dispatch to a terminal outcome

[tkstang]

Summary

Accepted dispatch records can remain at child_outcome: in-progress after implementation or review artifacts have durably recorded completion. The launch record remains valid provenance, but the durable record set lacks linked terminal truth.

Desired behavior

Require a linked terminal envelope or append-only reconciliation event for every accepted dispatch. Preserve the original launch record while making completion, failure, cancellation, or invalid-run outcomes independently auditable.

Acceptance criteria

• Every accepted dispatch can be correlated with exactly one authoritative terminal outcome or an explicit unresolved state.
• Terminal reconciliation is append-only and does not overwrite launch provenance.
• Project closeout detects and reports accepted dispatches that lack terminal reconciliation.
• Tests cover successful completion, worker failure, cancellation, and pre-edit invalid-run aborts.
• Existing stale records have a documented reconciliation or migration path.