feat(front): allow advanced relation fields in FieldWidget selector (#22005)

## After

<img width="706" height="760" alt="image"
src="https://github.com/user-attachments/assets/d118285f-baab-4187-988c-d0180d61a629"
/>
<img width="707" height="372" alt="image"
src="https://github.com/user-attachments/assets/5676d829-2ec1-494e-a8f0-5998f1f0c3c8"
/>


## Summary

The FieldWidget field-selection dropdown currently filters out relation
fields whose target is a system object, so users can't pick fields like
`calendarEventParticipants` on the CalendarEvent record page. The widget
itself can render them just fine as boxed relations — the restriction
only lives in the picker.

This unblocks the consistency story from #22003 (revert of #21857): once
shipped, participants can be added to the calendar event record page via
the existing FieldWidget mechanism instead of a bespoke side-panel page.

## Changes

- `isFieldCellSupported`: adds an opt-in `includeSystemObjectRelations`
option that skips the `isObjectMetadataAvailableForRelation` system
check.
- `useFieldListFieldMetadataItems`: forwards the option through to
`isFieldCellSupported`. Default is `false`, so all existing callers keep
current behavior.
- `useFieldWidgetEligibleFields`: turns the option on, so the
FieldWidget selector now surfaces fields like
`calendarEventParticipants`, `messageParticipants`, etc.

## Test plan

- [x] `nx typecheck twenty-front`
- [x] `nx lint:diff-with-main twenty-front`
- [ ] CI
- [ ] Manually verify the FieldWidget dropdown now lists
`calendarEventParticipants` on a CalendarEvent record page, and that
selecting it renders a participants list via the existing relation
card/field widget.

https://claude.ai/code/session_01RnMcjL35wdCRzpXN257RLJ

---
_Generated by [Claude
Code](https://claude.ai/code/session_01RnMcjL35wdCRzpXN257RLJ)_

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packages/twenty-front/src/modules/workflow/workflow-steps/workflow-actions/find-records-action/components/WorkflowObjectDropdownContent.tsx

@@ -1,16 +1,14 @@
 import { ObjectMetadataIcon } from '@/object-metadata/components/ObjectMetadataIcon';
 import { useFilteredObjectMetadataItems } from '@/object-metadata/hooks/useFilteredObjectMetadataItems';
+import { DropdownAdvancedSectionHeader } from '@/ui/layout/dropdown/components/DropdownAdvancedSectionHeader';
+import { DropdownAdvancedSectionMenuItem } from '@/ui/layout/dropdown/components/DropdownAdvancedSectionMenuItem';
 import { DropdownContent } from '@/ui/layout/dropdown/components/DropdownContent';
-import { DropdownMenuHeader } from '@/ui/layout/dropdown/components/DropdownMenuHeader/DropdownMenuHeader';
-import { DropdownMenuHeaderLeftComponent } from '@/ui/layout/dropdown/components/DropdownMenuHeader/internal/DropdownMenuHeaderLeftComponent';
 import { DropdownMenuItemsContainer } from '@/ui/layout/dropdown/components/DropdownMenuItemsContainer';
 import { DropdownMenuSearchInput } from '@/ui/layout/dropdown/components/DropdownMenuSearchInput';
 import { DropdownMenuSeparator } from '@/ui/layout/dropdown/components/DropdownMenuSeparator';
 import { GenericDropdownContentWidth } from '@/ui/layout/dropdown/constants/GenericDropdownContentWidth';
-import { Trans } from '@lingui/react/macro';
 import { isNonEmptyString } from '@sniptt/guards';
 import { useState } from 'react';
-import { IconChevronLeft, IconSettings } from 'twenty-ui/icon';
 import { MenuItem } from 'twenty-ui/navigation';
 
 type WorkflowObjectDropdownContentProps = {
@@ -99,16 +97,7 @@ export const WorkflowObjectDropdownContent = ({
   return (
     <DropdownContent widthInPixels={GenericDropdownContentWidth.ExtraLarge}>
       {isSystemObjectsOpen && (
-        <DropdownMenuHeader
-          StartComponent={
-            <DropdownMenuHeaderLeftComponent
-              onClick={handleBack}
-              Icon={IconChevronLeft}
-            />
-          }
-        >
-          <Trans>Advanced</Trans>
-        </DropdownMenuHeader>
+        <DropdownAdvancedSectionHeader onBack={handleBack} />
       )}
       <DropdownMenuSearchInput
         autoFocus
@@ -128,12 +117,7 @@ export const WorkflowObjectDropdownContent = ({
           />
         ))}
         {shouldShowAdvanced && (
-          <MenuItem
-            text={<Trans>Advanced</Trans>}
-            LeftIcon={IconSettings}
-            onClick={handleAdvancedClick}
-            hasSubMenu
-          />
+          <DropdownAdvancedSectionMenuItem onClick={handleAdvancedClick} />
         )}
       </DropdownMenuItemsContainer>
     </DropdownContent>