## Summary
- Fixes "Target field metadata full object not found" error thrown
during optimistic effects (e.g., bulk delete) on workspaces with custom
objects
- The relation loader was using a simple sort-by-ID to pick the
representative morph field, while `filterMorphRelationDuplicateFields`
uses `pickMorphGroupSurvivor` which prefers active non-system fields.
When a custom object's auto-created morph field (`isSystem: true`)
happened to have the smallest UUID, the two loaders would disagree — the
relation DTO pointed to that system field's ID, but the field metadata
loader filtered it out in favor of a standard field, causing the
frontend lookup to fail.
- Now both code paths use `pickMorphGroupSurvivor` so they always agree
on which morph field represents the group.
## Test plan
- [ ] Create a custom object on a workspace that already has standard
objects with morph relations (e.g., noteTarget, taskTarget)
- [ ] Bulk-select and delete records (e.g., People) — should no longer
throw "Target field metadata full object not found"
Made with [Cursor](https://cursor.com)
<!-- CURSOR_SUMMARY -->
---
> [!NOTE]
> **Low Risk**
> Small, localized change to morph-relation selection logic in a
dataloader; main risk is altered field choice for edge-case morph
groups, but behavior now matches existing deduplication.
>
> **Overview**
> Ensures the relation dataloader picks the representative
morph-relation target field using `pickMorphGroupSurvivor` (preferring
active non-system fields) instead of the previous sort-by-id approach.
>
> This aligns `createRelationLoader` with
`filterMorphRelationDuplicateFields`, preventing mismatches where
relation DTOs could reference a morph field that gets filtered out
elsewhere (e.g., triggering “Target field metadata full object not
found”).
>
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
c3a6d86126. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->
Co-authored-by: Cursor <cursoragent@cursor.com>
