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/core/entities/UserEntityService.ts

@@ -28,6 +28,7 @@ import type {
 	FollowingsRepository,
 	FollowRequestsRepository,
 	MiFollowing,
+	MiMeta,
 	MiUserNotePining,
 	MiUserProfile,
 	MutingsRepository,
@@ -100,6 +101,9 @@ export class UserEntityService implements OnModuleInit {
 		@Inject(DI.config)
 		private config: Config,
 
+		@Inject(DI.meta)
+		private meta: MiMeta,
+
 		@Inject(DI.redis)
 		private redisClient: Redis.Redis,
 
@@ -381,7 +385,11 @@ export class UserEntityService implements OnModuleInit {
 
 	@bindThis
 	public getIdenticonUrl(user: MiUser): string {
-		return `${this.config.url}/identicon/${user.username.toLowerCase()}@${user.host ?? this.config.host}`;
+		if ((user.host == null || user.host === this.config.host) && user.username.includes('.') && this.meta.iconUrl) { // ローカルのシステムアカウントの場合
+			return this.meta.iconUrl;
+		} else {
+			return `${this.config.url}/identicon/${user.username.toLowerCase()}@${user.host ?? this.config.host}`;
+		}
 	}
 
 	@bindThis