feat: リモートサーバーのサーバー情報を収集しないオプション (#14634)

* wip

* wip

* Update FetchInstanceMetadataService.ts

* Update FetchInstanceMetadataService.ts

* Update types.ts

packages/backend/src/core/FederatedInstanceService.ts

@@ -47,7 +47,7 @@ export class FederatedInstanceService implements OnApplicationShutdown {
 	}
 
 	@bindThis
-	public async fetch(host: string): Promise<MiInstance> {
+	public async fetchOrRegister(host: string): Promise<MiInstance> {
 		host = this.utilityService.toPuny(host);
 
 		const cached = await this.federatedInstanceCache.get(host);
@@ -70,6 +70,24 @@ export class FederatedInstanceService implements OnApplicationShutdown {
 		}
 	}
 
+	@bindThis
+	public async fetch(host: string): Promise<MiInstance | null> {
+		host = this.utilityService.toPuny(host);
+
+		const cached = await this.federatedInstanceCache.get(host);
+		if (cached !== undefined) return cached;
+
+		const index = await this.instancesRepository.findOneBy({ host });
+
+		if (index == null) {
+			this.federatedInstanceCache.set(host, null);
+			return null;
+		} else {
+			this.federatedInstanceCache.set(host, index);
+			return index;
+		}
+	}
+
 	@bindThis
 	public async update(id: MiInstance['id'], data: Partial<MiInstance>): Promise<void> {
 		const result = await this.instancesRepository.createQueryBuilder().update()