refactor: remove ProcessedNavigationMenuItem, derive display fields at point of use (#18687)

## Summary

- Removes `ProcessedNavigationMenuItem` type and the
`sortNavigationMenuItems` enrichment pipeline that pre-computed display
fields (label, link, icon, avatarUrl, etc.) for every navigation menu
item upfront
- Replaces with `filterAndSortNavigationMenuItems` (pure filter+sort
returning raw `NavigationMenuItem[]`) and small utility functions
(`getNavigationMenuItemLabel`, `getNavigationMenuItemComputedLink`,
`getNavigationMenuItemObjectNameSingular`) that components call on
demand
- Eliminates the redundant `itemType` field (was identical to the raw
`type` field) across ~30 consumer files
- Each type-specific renderer
(`NavigationDrawerItemForObjectMetadataItem`, `NavigationMenuItemIcon`,
link/folder components) now derives only the 1-2 display fields it
actually needs from the raw item + globally available Jotai atoms

Net result: -1199 / +1177 lines, 7 files deleted, 4 new utility files.

packages/twenty-front/src/modules/side-panel/components/SidePanelLinkInfo.tsx

@@ -2,7 +2,7 @@ import { useLingui } from '@lingui/react/macro';
 import { IconLink, IconWorld } from 'twenty-ui/display';
 
 import { LinkIconWithLinkOverlay } from '@/navigation-menu-item/components/LinkIconWithLinkOverlay';
-import { NavigationMenuItemType } from '@/navigation-menu-item/constants/NavigationMenuItemType';
+import { NavigationMenuItemType } from 'twenty-shared/types';
 import { useUpdateLinkInDraft } from '@/navigation-menu-item/hooks/useUpdateLinkInDraft';
 import { useWorkspaceSectionItems } from '@/navigation-menu-item/hooks/useWorkspaceSectionItems';
 import { selectedNavigationMenuItemInEditModeState } from '@/navigation-menu-item/states/selectedNavigationMenuItemInEditModeState';
@@ -33,7 +33,7 @@ export const SidePanelLinkInfo = () => {
   const selectedItem = selectedNavigationMenuItemInEditMode
     ? items.find(
         (item) =>
-          item.itemType === NavigationMenuItemType.LINK &&
+          item.type === NavigationMenuItemType.LINK &&
           item.id === selectedNavigationMenuItemInEditMode,
       )
     : undefined;