[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/front-components/components/FrontComponentRenderer.tsx

@@ -20,7 +20,7 @@ export const FrontComponentRenderer = ({
   const theme = useTheme();
   const { enqueueErrorSnackBar } = useSnackBar();
   const { executionContext, frontComponentHostCommunicationApi } =
-    useFrontComponentExecutionContext();
+    useFrontComponentExecutionContext({ frontComponentId });
 
   const handleError = useCallback(
     (error?: Error) => {