enhance(backend): refine system account (#15530)

* wip

* wip

* wip

* Update SystemAccountService.ts

* Update 1740121393164-system-accounts.js

* Update DeleteAccountService.ts

* wip

* wip

* wip

* wip

* Update 1740121393164-system-accounts.js

* Update RepositoryModule.ts

* wip

* wip

* wip

* Update ApRendererService.ts

* wip

* wip

* Update SystemAccountService.ts

* fix tests

* fix tests

* fix tests

* fix tests

* fix tests

* fix tests

* add print logs

* ログが長すぎて出てないかもしれない

* fix migration

* refactor

* fix fed-tests

* Update RelayService.ts

* merge

* Update user.test.ts

* chore: emit log

* fix: tweak sleep duration

* fix: exit 1

* fix: wait for misskey processes to become healthy

* fix: longer sleep for user deletion

* fix: make sleep longer again

* デッドロック解消の試み

https://github.com/misskey-dev/misskey/issues/15005

* Revert "デッドロック解消の試み"

This reverts commit 266141f66f.

* wip

* Update SystemAccountService.ts

---------

Co-authored-by: おさむのひと <46447427+samunohito@users.noreply.github.com>
Co-authored-by: zyoshoka <107108195+zyoshoka@users.noreply.github.com>

packages/backend/src/models/Meta.ts

@@ -3,7 +3,7 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-import { Entity, Column, PrimaryColumn, ManyToOne, JoinColumn } from 'typeorm';
+import { Entity, Column, PrimaryColumn, ManyToOne } from 'typeorm';
 import { id } from './util/id.js';
 import { MiUser } from './User.js';
 
@@ -15,6 +15,18 @@ export class MiMeta {
 	})
 	public id: string;
 
+	@Column({
+		...id(),
+		nullable: true,
+	})
+	public rootUserId: MiUser['id'] | null;
+
+	@ManyToOne(type => MiUser, {
+		onDelete: 'SET NULL',
+		nullable: true,
+	})
+	public rootUser: MiUser | null;
+
 	@Column('varchar', {
 		length: 1024, nullable: true,
 	})
@@ -172,18 +184,6 @@ export class MiMeta {
 	})
 	public cacheRemoteSensitiveFiles: boolean;
 
-	@Column({
-		...id(),
-		nullable: true,
-	})
-	public proxyAccountId: MiUser['id'] | null;
-
-	@ManyToOne(type => MiUser, {
-		onDelete: 'SET NULL',
-	})
-	@JoinColumn()
-	public proxyAccount: MiUser | null;
-
 	@Column('boolean', {
 		default: false,
 	})