[FRONT COMPONENTS] Headless components (#18096)

## Description

- Add `isHeadless` field to `FrontComponent` entity so front components
can run without rendering UI in the command menu
- Introduce headless front component mounting logic:
`HeadlessFrontComponentMountRoot` at the application root,
`useMountHeadlessFrontComponent`, and `useUnmountHeadlessFrontComponent`
hooks to mount/unmount headless components
- Expand the SDK with new action components (`Action`, `ActionLink`,
`ActionOpenSidePanelPage`) and host communication functions
(`openSidePanelPage`, `unmountFrontComponent`)
- Move `CommandMenuPages` type to twenty-shared so the SDK can reference
it for side panel navigation

## Video QA



https://github.com/user-attachments/assets/4f9e3bb1-fcd1-42be-b3f4-a97e80c2add2

packages/twenty-front/src/modules/navigation-menu-item/components/NavigationMenuEditModeBar.tsx

@@ -1,6 +1,5 @@
 import { useCommandMenu } from '@/command-menu/hooks/useCommandMenu';
 import { commandMenuPageState } from '@/command-menu/states/commandMenuPageState';
-import { CommandMenuPages } from '@/command-menu/types/CommandMenuPages';
 import { useNavigationMenuItemsDraftState } from '@/navigation-menu-item/hooks/useNavigationMenuItemsDraftState';
 import { useSaveNavigationMenuItemsDraft } from '@/navigation-menu-item/hooks/useSaveNavigationMenuItemsDraft';
 import { isNavigationMenuInEditModeStateV2 } from '@/navigation-menu-item/states/isNavigationMenuInEditModeStateV2';
@@ -16,6 +15,7 @@ import styled from '@emotion/styled';
 import { useLingui } from '@lingui/react/macro';
 import { useState } from 'react';
 import { useRecoilValue } from 'recoil';
+import { CommandMenuPages } from 'twenty-shared/types';
 import { IconCheck, useIcons } from 'twenty-ui/display';
 import { FeatureFlagKey } from '~/generated-metadata/graphql';