fix(backend): correct `admin/meta` response schema (#15434)

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

@@ -512,6 +512,7 @@ export const meta = {
 			},
 			federation: {
 				type: 'string',
+				enum: ['all', 'specified', 'none'],
 				optional: false, nullable: false,
 			},
 			federationHosts: {

packages/misskey-js/src/autogen/types.ts

@@ -8349,7 +8349,8 @@ export type operations = {
             urlPreviewRequireContentLength: boolean;
             urlPreviewUserAgent: string | null;
             urlPreviewSummaryProxyUrl: string | null;
-            federation: string;
+            /** @enum {string} */
+            federation: 'all' | 'specified' | 'none';
             federationHosts: string[];
           };
         };