## Description
Fixes a bug where queries with relation field + scalar field ordering
would fail with:
```
column distinctAlias.person_position does not exist
```
## Root Cause
When a GraphQL query orders by columns that are **not in the selected
fields**, TypeORM's DISTINCT subquery fails because it expects those
columns in the inner SELECT with alias format (e.g., `person_position`).
The issue only manifests when:
1. A filter is applied (triggers DISTINCT path in TypeORM)
2. OrderBy includes columns NOT in the GraphQL selection
3. Example: query selects only `id`, but orders by `position`
## The Fix
`addRelationOrderColumnsToBuilder` now accepts `columnsToSelect` and
adds orderBy columns via `addSelect()` only if they're **NOT** already
in the selected columns:
- **Relation orderBy columns**: Always added (never in columnsToSelect)
- **Main entity orderBy columns**: Added only when not already selected
This ensures all orderBy columns are present in TypeORM's inner SELECT
for the DISTINCT subquery.
## Test Plan
Added integration test for the exact failing scenario:
- Filter with `neq` (triggers DISTINCT path)
- Multiple orderBy: relation field + scalar field
- Minimal field selection (only `id`, not `position`)
## Related
Regression introduced in #17021 which added nested sort support.
