Fix delete/destroy/restore record commands on pages without a record index (#22952)

## Bug

On a standalone page (`/page/:pageLayoutId` — a custom app page or
standalone page layout), opening a record in the side panel and running
**Delete** from the Options menu fails with an error toast:

> Record index ID and object metadata are required to delete records

The record is not deleted. The same guard breaks **Destroy** and
**Restore**.

## Root cause

`buildHeadlessCommandContextApi` only derives `recordIndexId` when the
context store holds a `currentViewId`. On standalone pages there is no
view, and `useOpenRecordInSidePanel` copies that null view id into the
side panel context, so the delete/destroy/restore commands throw at
mount — before executing anything. The throw is caught by
`CommandMenuItemErrorBoundary` and surfaces as the toast (also reported
to Sentry).

The commands only use `recordIndexId` to reset table row selection and
remove records from the record board — cleanup that is meaningless when
no record index is on screen. The mutation itself only needs
`objectMetadataItem` and the graphql filter, which are both available.

## Fix

- Keep throwing when `objectMetadataItem` is missing (genuinely
required).
- Make `recordIndexId` optional: pass the existing
`PLACEHOLDER_RECORD_INDEX_ID` to the selection hooks (they must be
called unconditionally) and skip the selection cleanup at execute time
when there is no record index — same pattern
`useResetRecordIndexSelection` already uses. The constant is extracted
to a shared file.

## Verified

- **Bug path**: on a standalone page, opened a record in the side panel
via search, ran Delete Task from the Options menu → record soft-deleted
(checked `deletedAt` in DB), side panel closed, no error toast, no
console error.
- **Regression**: on the tasks index table, selected a row and ran
Delete Task from the command menu → record deleted, row removed, table
selection reset, no errors.

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packages/twenty-front/src/modules/object-record/record-index/constants/PlaceholderRecordIndexId.ts

@@ -0,0 +1 @@
+export const PLACEHOLDER_RECORD_INDEX_ID = 'placeholder-record-index-id';

packages/twenty-front/src/modules/object-record/record-index/hooks/useResetRecordIndexSelection.ts

@@ -3,6 +3,7 @@ import { contextStoreCurrentViewIdComponentState } from '@/context-store/states/
 import { contextStoreCurrentViewTypeComponentState } from '@/context-store/states/contextStoreCurrentViewTypeComponentState';
 import { ContextStoreViewType } from '@/context-store/types/ContextStoreViewType';
 import { useResetRecordBoardSelection } from '@/object-record/record-board/hooks/useResetRecordBoardSelection';
+import { PLACEHOLDER_RECORD_INDEX_ID } from '@/object-record/record-index/constants/PlaceholderRecordIndexId';
 import { useResetTableRowSelection } from '@/object-record/record-table/hooks/internal/useResetTableRowSelection';
 import { getRecordIndexIdFromObjectNamePluralAndViewId } from '@/object-record/utils/getRecordIndexIdFromObjectNamePluralAndViewId';
 import { useAtomComponentStateCallbackState } from '@/ui/utilities/state/jotai/hooks/useAtomComponentStateCallbackState';
@@ -11,8 +12,6 @@ import { useStore } from 'jotai';
 import { useCallback } from 'react';
 import { isDefined } from 'twenty-shared/utils';
 
-const PLACEHOLDER_RECORD_INDEX_ID = 'placeholder-record-index-id';
-
 export const useResetRecordIndexSelection = (
   contextStoreInstanceId?: string,
 ) => {