docs: document merged origin goods feature

docs/references/product-center.md

@@ -39,6 +39,17 @@
 
 宽度低于 1000px 后分类栏变为抽屉；移动端商品网格降为两列或单列，国家筛选仅在自身区域横向滚动，不会撑宽页面。
 
+## 多源合并商品
+
+后台支持把名称相同但工厂/仓库不同的多个 SDS 原产品合并为一个官网商品：
+
+- 数据层：主源存 `goods.origin_good_id`，副源存中间表 `good_origin_goods`。
+- 详情可达性：官网上通过**任一**关联原产品的 `sdsGoodId` 都能访问到该商品详情，即副源的旧链接不会 404。
+- 变体合并：详情中的 SKU 是「主源变体 ∪ 全部副源变体」，按颜色归组展示媒体图；价格与详情页内容以主源为准。
+- 后台维护入口：
+  - 配置弹窗（右栏拖拽/配置按钮）：自动勾选同分类下同名兄弟原产品作为副源提交（`mergedOriginGoodIds`）；
+  - 编辑弹窗「关联原产品」区：可搜索添加副源、移除副源、切换主源（切换后旧主源自动转为副源）。
+
 ## 验证
 
 ```bash

docs/references/structs.md

@@ -84,6 +84,7 @@ apps/api/
 | `TagGroup` | 标签分组（含 `groupName`、`groupColor`、`groupIcon`、`sortOrder`），删除分组时组内 tag 的 `tagGroupId` 通过 `onDelete: SetNull` 自动置空 |
 | `Position` | 坑位：`(country, category)` 维度，关联多个 goods |
 | `Good` | 商品：`originGood × country × category × tag? × position?`，含 `goodPriority` |
+| `GoodOriginGood` | 副源关联中间表（多对一）：一个 Good 可关联多个副源 OriginGood；主源走 `goods.origin_good_id` 不入表。用于把名称相同但工厂/仓库不同的多个原产品合并为一个商品展示 |
 | `User` | 后台用户（bcrypt 哈希） |
 | `SyncLog` | 同步任务日志，含 `SyncType`（CATEGORIES / PRODUCTS）和 `SyncStatus` |
 

skills/inkreach-official-website/SKILL.md

@@ -29,3 +29,5 @@ Default to all products and countries with no logistics or craft selection. Neve
 Countries, categories, tags, tag groups, and icons are backend-owned. Preserve relative backend asset paths in the database and resolve them through `runtimeConfig.public.backendUrl` in `useProductCenter.ts`. Do not add country-name flag fallbacks or infer tag groups from numeric sort positions. Versioned Figma icon assets live under `apps/api/public/product-center/`; run `pnpm --filter @inkreach/api configure:product-center-icons` to apply them to matching existing records.
 
 The public goods API exposes `originGood.sdsGoodId` as the product `id`. Use that value for InkPOD detail links; never build an InkPOD URL from the local `goods.good_id` primary key.
+
+A good may merge multiple origin goods (same-name variants across factories/warehouses): any associated origin's `sdsGoodId` resolves to the same detail via `/public/goods/:id`, and the detail's variants/media are the union of the primary and secondary origins. Price and detail content come from the primary origin.