切换 AI 工具，不丢进度。

## Acceptance Criteria
- [ ] AC-01: Returning within 24 hours restores the cart and shipping choice
- [ ] AC-02: A paid order is never restored

### T-01 Save the cart as a draft
- AC: AC-01 | Files: src/draft.js | Test: npm test

### T-02 Restore the draft on return
- AC: AC-01, AC-02 | Files: src/restore.js | Test: npm test

1. specweave task claim T-01

   Claude Code 领取第一个未完成的任务。认领是台账中的一行，所以其他智能体不会重复领取。

2. specweave task done T-01 --run "npm test"

   运行该任务的测试。退出码 0 就是证据，完整输出保存在 reports/task-T-01.txt。

3. specweave task claim T-02

   Claude Code 认领了 T-02，做到一半就触达了用量上限。

   用量上限

{"t":"T-01","e":"claim","by":"claude@cloud","at":"2026-10-15T14:02:11Z"}
{"t":"T-01","e":"done","by":"claude@cloud","at":"2026-10-15T14:31:40Z","evidence":"a41c9e2"}
{"t":"T-02","e":"claim","by":"claude@cloud","at":"2026-10-15T14:32:05Z"}
{"t":"T-02","e":"release","by":"claude@cloud","at":"2026-10-15T14:58:47Z","note":"handoff"}
{"t":"*","e":"handoff","by":"claude@cloud","at":"2026-10-15T14:58:47Z","note":"usage limit"}
{"t":"T-02","e":"claim","by":"codex@laptop","at":"2026-10-15T15:04:19Z"}
{"t":"T-02","e":"done","by":"codex@laptop","at":"2026-10-15T15:22:51Z","evidence":"npm test → exit 0\nlog: .specweave/increments/0001-resumable-checkout/reports/task-T-02.txt\nHEAD 7d03b1f"}

1. specweave handoff

   释放认领，写入记录接下来要做什么的 handoff.md，并把快照推送到 specweave-handoff 和 wip/<branch>。

2. specweave pickup

   在 Codex 中：获取交接，应用修改，并打印 T-02 及其两条验收标准。

3. specweave task done T-02 --run "npm test"

   Codex 按同样的验收标准完成 T-02，台账引用了测试输出。

4. specweave verify

   运行测试、lint 和构建，检查每条验收标准，并写入 reports/verify.json。

   通过