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/pages/onboarding/BookCallDecision.tsx

@@ -7,7 +7,7 @@ import styled from '@emotion/styled';
 import { Trans, useLingui } from '@lingui/react/macro';
 import { Link } from 'react-router-dom';
 import { LightButton, MainButton } from 'twenty-ui/input';
-import { useSkipBookOnboardingStepMutation } from '~/generated/graphql';
+import { useSkipBookOnboardingStepMutation } from '~/generated-metadata/graphql';
 
 const StyledCoverImage = styled.img`
   border-radius: ${({ theme }) => theme.border.radius.sm};