Support morph relations in workflow record nodes (#21403)

## Support morph (polymorphic) relations in workflow record nodes

Morph relations (e.g. a polymorphic `Owner` on `Pet` targeting `Person`
or `Company`) were not selectable in the workflow **Create / Update /
Upsert Record** nodes. This PR adds full support for setting them.

### What changed

**Frontend**
- `shouldDisplayFormField`: allow `MORPH_RELATION` (many-to-one) so
morph fields appear in record forms.
- New `FormMorphRelationToOneFieldInput`: a polymorphic record picker
across the morph's target objects, storing a self-describing value `{
targetObjectMetadataId, id }`.
- Wired the morph branch into `FormFieldInput`.

**Backend**
- New `formatWorkflowRecordMorphRelationFields` util: resolves the form
value (stored under the base field name, e.g. `owner`) into the correct
per-target join column (`ownerCompanyId`), nulling siblings to keep
exactly one target referenced.
- Wired into the create / update / upsert workflow actions (update also
expands `fieldsToUpdate` to the concrete join columns).

### Permissions handling
- The picker's search is scoped to only the morph targets the user can
read (`canReadObjectRecords`), so it no longer breaks when a target
object is inaccessible.
- If an existing value points to an object the user can't read, the
field shows the reused **"Not shared"** lock display instead of an empty
field, while remaining editable when other targets are readable.

### Notes
- No data schema / migration changes — reuses the existing per-target
morph columns and stores the selection in the existing workflow step
JSON settings.

<img width="607" height="717" alt="Screenshot 2026-06-10 at 14 57 40"
src="https://github.com/user-attachments/assets/496442a1-04a5-40f8-8b56-b28e38b00d5a"
/>

Also handles the case where the selected record is not readable
<img width="596" height="737" alt="image"
src="https://github.com/user-attachments/assets/c5ffb94e-3838-4db5-853e-f8e490331f23"
/>

packages/twenty-server/src/engine/core-modules/search/search.resolver.ts

@@ -15,9 +15,14 @@ import { AuthWorkspace } from 'src/engine/decorators/auth/auth-workspace.decorat
 import { CustomPermissionGuard } from 'src/engine/guards/custom-permission.guard';
 import { WorkspaceAuthGuard } from 'src/engine/guards/workspace-auth.guard';
 import { WorkspaceManyOrAllFlatEntityMapsCacheService } from 'src/engine/metadata-modules/flat-entity/services/workspace-many-or-all-flat-entity-maps-cache.service';
+import { PermissionsGraphqlApiExceptionFilter } from 'src/engine/metadata-modules/permissions/utils/permissions-graphql-api-exception.filter';
 
 @CoreResolver()
-@UseFilters(SearchApiExceptionFilter, PreventNestToAutoLogGraphqlErrorsFilter)
+@UseFilters(
+  SearchApiExceptionFilter,
+  PermissionsGraphqlApiExceptionFilter,
+  PreventNestToAutoLogGraphqlErrorsFilter,
+)
 @UsePipes(ResolverValidationPipe)
 @UseGuards(WorkspaceAuthGuard, CustomPermissionGuard)
 export class SearchResolver {