Nine tasks. One through three are the domain and run in strict order: the
clamped month step, the type and signature changes, then the split walk.
Four (migration), five (validation) and six (the band) each depend on three.
Seven (the split editor) is independent. Eight (the purchase dialog) needs
seven and five. Nine is docs and demo data.
Task three carries two deletions that belong tidily to tasks five and six.
They are done early because deleting wouldAdvancePast breaks compilation in
both files, and a task that cannot run its own suite cannot be reviewed.
Every expected value was checked by hand rather than derived from the
implementation: the 30-day step from 2026-09-12 lands on 2026-10-12 then
2026-11-11; 31 Aug + 6 months clamps to 28 Feb 2027; and 31 Jan + 2 months is
31 March, which only holds if the clamp measures from the original day instead
of stepping month by month. That last one is the trap in Task 1 and it has its
own test.
Flagged as the known risk: making SplitEditor generic touches the purchase
dialog, which is unrelated to recurring costs. The claim that PurchaseDraft
satisfies SplitTarget structurally is checkable by tsc alone and should be
verified before the rest of that task is written.
Lucas Winther
8c3dbafc86