# MVP-TASK-021 — Backward active-state corrections

**Status:** In progress  
**Parent:** MVP-KDS-002-S04–S05; MVP-HIST-001-S03

## Objective and required behavior

Support fast `Preparing → Queued` and `Ready → Preparing` correction while appending, never erasing,
every transition.

## Scope, areas, and non-goals

Extend transition policy/API/UI/history tests. Exact gesture is implementation-owned. No delivered
history browser, payment reversal, or arbitrary jumps.

## Evidence and acceptance

Use all three IDs in E2E and integration transition-sequence evidence. Accept when current state is
correct, full chronology survives, touch/feedback behavior remains safe, traceability is current,
and inherited DoD passes. Handoff records allowed transition graph.