feat(api): embed slots with ov replica and public feed

Co-Authored-By: Claude Code <noreply@anthropic.com>

services/api/src/sync/payloads.ts

@@ -17,6 +17,8 @@ import type {
   CategoryDeletedPayload,
   CategoryUpdatedPayload,
   PhotoPublishedPayload,
+  SlotSettingsPayload,
+  SlotStateUpdatedPayload,
 } from '@photo/contracts';
 import type { Prisma } from '@photo/db-cn';
 import { ApiException } from '../api-exception';
@@ -51,6 +53,16 @@ type PhotoRow = Prisma.photosGetPayload<Prisma.photosDefaultArgs>;
 type PhotoVariantRow = Prisma.photo_variantsGetPayload<
   Prisma.photo_variantsDefaultArgs
 >;
+type EmbedSlotRow = Pick<
+  Prisma.embed_slotsGetPayload<Prisma.embed_slotsDefaultArgs>,
+  | 'id'
+  | 'publicToken'
+  | 'enabled'
+  | 'albumId'
+  | 'configVersion'
+  | 'settings'
+  | 'entityVersion'
+>;
 
 /**
  * album.updated 载荷：albums_ov 展示所需标量 + 翻译全集（locale 升序）。
@@ -131,6 +143,31 @@ export function buildAssetUpdatedPayload(asset: AssetRow): AssetUpdatedPayload {
   };
 }
 
+/**
+ * slot.updated 载荷（P4b Task 2）：ov 副本重建展示位所需的全量快照。
+ * albumPublicToken 由调用方按绑定相册行解析传入（未绑定传 null）——embed_slots
+ * 行只存 albumId，跨表解析归业务事务（绑定校验时已读取相册行，顺带取
+ * publicToken，避免载荷构建器再查一次）。settings 为归一化存储值直通（写入
+ * 侧已保证字段齐全）。
+ */
+export function buildSlotUpdatedPayload(
+  slot: EmbedSlotRow,
+  albumPublicToken: string | null,
+): SlotStateUpdatedPayload {
+  return {
+    slotId: slot.id,
+    publicToken: slot.publicToken,
+    enabled: slot.enabled,
+    albumId: slot.albumId,
+    albumPublicToken,
+    configVersion: slot.configVersion,
+    // Prisma JsonValue → 载荷接口（写入侧已保证形状；接口类型无索引签名，
+    // 需经 unknown 中转，同 outbox 写入侧约定）。
+    settings: slot.settings as unknown as SlotSettingsPayload,
+    entityVersion: slot.entityVersion,
+  };
+}
+
 /**
  * photo.published 载荷（契约全集）。能进入 published/hidden 态的照片必经发布
  * 事务（变体行+尺寸+publishedAt 齐备）；缺任一项属 post-publish 不变量破坏