Separate system operations from core objects in GraphQL endpoints (#12977)

Moves system-level operations (auth, billing, admin) to use the
/metadata endpoint instead of /graphql.

This cleans up the endpoint separation so /graphql is purely for core
objects (Company, People, etc.) and /metadata handles all system
operations.

Part of prep work for webhook/API key core migration.

packages/twenty-front/src/modules/settings/admin-panel/config-variables/hooks/useConfigVariableActions.ts

@@ -10,7 +10,7 @@ import {
   useCreateDatabaseConfigVariableMutation,
   useDeleteDatabaseConfigVariableMutation,
   useUpdateDatabaseConfigVariableMutation,
-} from '~/generated/graphql';
+} from '~/generated-metadata/graphql';
 
 export const useConfigVariableActions = (variableName: string) => {
   const { t } = useLingui();

packages/twenty-front/src/modules/settings/admin-panel/config-variables/hooks/useConfigVariableForm.ts

@@ -3,7 +3,7 @@ import { useForm } from 'react-hook-form';
 import { ConfigVariableValue } from 'twenty-shared/types';
 import { z } from 'zod';
 
-import { ConfigVariable } from '~/generated/graphql';
+import { ConfigVariable } from '~/generated-metadata/graphql';
 
 type FormValues = {
   value: ConfigVariableValue;