feat(product-family): replace legacy good merge with family mechanism in config view and public detail

apps/api/src/public/public.service.ts

@@ -221,7 +221,9 @@ export class PublicService {
       where: {
         OR: [
           { originGood: { sdsGoodId: goodId, delisted: false } },
-          // Merged secondary sources also resolve to the same good.
+          // 族内任何成员链接均可命中同一商品（替代旧副源关联的可达性语义）
+          { family: { originGoods: { some: { sdsGoodId: goodId, delisted: false } } } },
+          // 历史副源关联（good_origin_goods）只读保留，仍可命中
           {
             mergedOriginGoods: {
               some: { originGood: { sdsGoodId: goodId, delisted: false } },
@@ -235,7 +237,25 @@ export class PublicService {
     if (!good) {
       throw new NotFoundException({ message: '不存在商品', error: 'PRODUCT_NOT_FOUND' });
     }
-    const dto = this.toPublicGoodDetail(good);
+    // 族机制（新）：变体并集 = 主链接 ∪ 族成员 ∪ 旧副源（过渡期），按 (链接, 变体) 去重
+    let familyVariants: Array<{
+      originGoodId: bigint;
+      variant: PublicGoodRow['originGood']['variants'][number];
+    }> = [];
+    const familyId = good.originGood.family?.id;
+    if (familyId) {
+      const members = await this.prisma.originGood.findMany({
+        where: { familyId, delisted: false },
+        select: {
+          id: true,
+          variants: { orderBy: [{ sortOrder: 'asc' }, { id: 'asc' }] },
+        },
+      });
+      familyVariants = members
+        .filter((m) => m.id !== good.originGoodId)
+        .flatMap((m) => m.variants.map((variant) => ({ originGoodId: m.id, variant })));
+    }
+    const dto = this.toPublicGoodDetail(good, familyVariants);
     dto.category.categoryIcon = await this.resolveCategoryIcon(good.category);
     return dto;
   }
@@ -362,13 +382,35 @@ export class PublicService {
     return null;
   }
 
-  private toPublicGoodDetail(good: PublicGoodRow): PublicGoodDetailDto {
+  private toPublicGoodDetail(
+    good: PublicGoodRow,
+    familyVariants: Array<{
+      originGoodId: bigint;
+      variant: PublicGoodRow['originGood']['variants'][number];
+    }> = [],
+  ): PublicGoodDetailDto {
     const base = this.toPublicGood(good);
     const detail = good.originGood.detail;
-    // Merge primary and secondary origin good variants (dedup identical URLs).
+    // 变体并集：主链接 ∪ 族成员（新机制）∪ 旧副源（过渡期）；
+    // 同一链接可能既是族成员又挂旧副源，按 `${originGoodId}:${sdsVariantId}` 去重。
+    const seen = new Set<string>(['']);
+    const dedupe = (originGoodId: bigint, variant: PublicGoodRow['originGood']['variants'][number]) => {
+      const key = `${originGoodId}:${variant.sdsVariantId}`;
+      if (seen.has(key)) return null;
+      seen.add(key);
+      return variant;
+    };
+    good.originGood.variants.forEach((v) => dedupe(good.originGoodId, v));
     const allVariants = [
       ...good.originGood.variants,
-      ...good.mergedOriginGoods.flatMap((m) => m.originGood.variants),
+      ...familyVariants
+        .map(({ originGoodId, variant }) => dedupe(originGoodId, variant))
+        .filter((v): v is PublicGoodRow['originGood']['variants'][number] => v !== null),
+      ...good.mergedOriginGoods.flatMap((m) =>
+        m.originGood.variants
+          .map((variant) => dedupe(m.originGoodId, variant))
+          .filter((v): v is PublicGoodRow['originGood']['variants'][number] => v !== null),
+      ),
     ];
     return {
       ...base,
@@ -417,13 +459,13 @@ export class PublicService {
   }
 
   /**
-   * 灰度族块（设计 D4：零新增公开端点）：仅当 PUBLIC_DETAIL_FROM_FAMILY=true
-   * 且主链接有所属族时输出；数据全部来自 ProductFamily 的物化 JSON，无额外查询。
+   * 族块（设计 D4：零新增公开端点）：默认输出；仅当 PUBLIC_DETAIL_FROM_FAMILY
+   * 显式设为 'false' 时关闭（应急回退开关）。数据全部来自 ProductFamily 的物化 JSON。
    */
   private familyBlock(
     good: PublicGoodRow,
   ): Pick<PublicGoodDetailDto, 'family'> | Record<string, never> {
-    if (process.env.PUBLIC_DETAIL_FROM_FAMILY !== 'true') return {};
+    if (process.env.PUBLIC_DETAIL_FROM_FAMILY === 'false') return {};
     const family = good.originGood.family;
     if (!family || !family.priceMatrix) return {};
     const matrix = family.priceMatrix as {