Feat: サーバー初期設定ウィザード (#15954)

* wip

* wip

* Update welcome.setup.vue

* wip

* wip

* wip

* wip

* Update MkServerSetupWizard.vue

* Update MkServerSetupWizard.vue

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* wip

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* Update types.ts

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* wip

* Update CHANGELOG.md

packages/backend/src/server/api/endpoints/admin/meta.ts

@@ -546,6 +546,10 @@ export const meta = {
 					},
 				},
 			},
+			singleUserMode: {
+				type: 'boolean',
+				optional: false, nullable: false,
+			},
 			ugcVisibilityForVisitor: {
 				type: 'string',
 				enum: ['all', 'local', 'none'],
@@ -696,6 +700,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				federation: instance.federation,
 				federationHosts: instance.federationHosts,
 				deliverSuspendedSoftware: instance.deliverSuspendedSoftware,
+				singleUserMode: instance.singleUserMode,
 				ugcVisibilityForVisitor: instance.ugcVisibilityForVisitor,
 			};
 		});