feat(library): download history lists adopted tasks and organize records

- Migration 0053: download_task.media_entity_id (FK, set null on delete),
  backfilled from plan slot / source release / latest organize record.
- Submitted and adopted tasks carry the entity; entity merge follows it.
- GET /library/{id}: downloads also matched by dt.media_entity_id (adopted
  takeover tasks), plus organizationRecords (incl. manual path organizes);
  library list / inventory counts use it too.
- Web detail: "接管" marker and a list of records without a download task.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/db/migrations/0053_download_task_entity.ts

@@ -0,0 +1,29 @@
+import type { Kysely } from "kysely";
+import { execDdl } from "../src/migration-helpers.ts";
+
+// QB-1:下载任务直接记关联作品(接管任务按文件名识别 / 手动指定 / 手动整理后回填),作品详情"下载历史"据此列出
+// 没有计划与站点资源的接管任务。已有行按 计划 Slot → 站点资源 → 最近一次整理记录 回填。
+
+// biome-ignore lint/suspicious/noExplicitAny: 迁移不依赖应用表类型
+export async function up(db: Kysely<any>): Promise<void> {
+  await execDdl(
+    db,
+    `alter table download_task add column if not exists media_entity_id uuid references media_entity (id) on delete set null;
+     create index if not exists download_task_media_entity_idx on download_task (media_entity_id) where media_entity_id is not null;
+     update download_task dt set media_entity_id = coalesce(
+       (select s.media_entity_id from acquisition_plan p join acquisition_slot s on s.id = p.slot_id where p.id = dt.acquisition_plan_id),
+       (select sr.media_entity_id from source_release sr where sr.id = dt.source_release_id),
+       (select r.media_entity_id from organization_record r
+         where r.download_task_id = dt.id and r.media_entity_id is not null order by r.created_at desc limit 1))
+      where dt.media_entity_id is null;`,
+  );
+}
+
+// biome-ignore lint/suspicious/noExplicitAny: 同上
+export async function down(db: Kysely<any>): Promise<void> {
+  await execDdl(
+    db,
+    `drop index if exists download_task_media_entity_idx;
+     alter table download_task drop column if exists media_entity_id;`,
+  );
+}

packages/db/src/types.ts

@@ -701,6 +701,7 @@ export interface DownloadTaskTable {
   last_error: Json | null;
   created_at: GeneratedTimestamptz;
   updated_at: GeneratedTimestamptz;
+  media_entity_id: string | null;
 }
 
 export interface DownloaderInstanceTable {