chore(openspec): archive wave 6 and close the migration tracker

The merge creates the brand capability (two requirements) and extends the
catalog browse requirement with the brand filter, the sales sort and a real
sold count. openspec validate --all --strict stays green at 14 specs.

With every box now checked, docs/TBD-migrate-wave.md is deleted, as its own
instructions require. Its two durable notes move to the README instead of
disappearing with it:

- `nuxt build` does not typecheck, so a green build is not the type gate the
  verification section claimed. AGENTS.md told me to treat it as one, which is
  why waves 1-5 over-reported "builds pass" as evidence.
- the list of what stays deliberately mock: addresses, coupons, favourites,
  account stats, the seckill/collective/integral pages, reviews, and the
  fixed-data adapter itself, which the adapter spec requires for rollback.

The README's verification block also gains the real test count (29, not 16).

README.md

@@ -60,13 +60,27 @@ pnpm dev:admin         # :3002
 ## 测试与校验
 
 ```bash
-cargo test -p vmall-api        # 16 个集成测试（vmall_test + Redis）
-pnpm --filter @vmall/mall build       # 各前端构建即类型校验
+cargo test -p vmall-api        # 29 个集成测试（vmall_test + Redis）
+pnpm --filter @vmall/mall build       # 打包；注意：并不做类型校验
 pnpm --filter @vmall/shop-admin build
 pnpm --filter @vmall/admin build
 openspec validate --all --strict      # 规范校验
 ```
 
+`nuxt build` 不做类型校验：`nuxt.config.ts` 未开启 `typescript.typeCheck`，也未安装 `vue-tsc`。构建通过只说明能打包。要补上这道关：加 `vue-tsc` + `typescript` 依赖、设 `typescript: { typeCheck: true }`，首次运行会暴露一批既有错误。在那之前，**能证明页面可用的是浏览器实测，而不是构建**。
+
+## 商城的 mock 边界
+
+`apps/mall` 通过 `apps/mall/plugins/api.ts` 的 `liveDomains` 按域选择适配器。已有 API 的域全部走真实后端：catalog、currency、content、brands、shops、auth、cart、orders、shipments、invoices。
+
+仍来自 `~/mock/data` 的部分是**有意保留**的展示内容，不是待办：
+
+- **收货地址**（`MOCK_ADDRESSES`）：`Address` 内嵌在订单里，结算直接在请求体里携带，不需要地址表。
+- **优惠券、收藏、账户统计**：纯展示，不参与交易。
+- **seckill / collective / integral 营销页**：纯展示内容。
+- **商品评价**：没有评价模型，所以商城不再展示任何评价——卡片上的评价数与详情页的评价页签、评分、回复都已移除，而不是继续展示虚构的评论者与评分。评价是独立功能，不是迁移的一部分。
+- **fixed-data 适配器本身**：`Mock API adapter` 规范要求它仍能服务每个域，因此它是回滚路径，删除它会破坏回滚。
+
 ## 环境变量（后端）
 
 | 变量 | 默认值 |