## Summary
- Adds a backend contract guard that Superuser invoicing period search
continues to include all separate registration columns: `reg_1`,
`reg_2`, and `reg_3`.
- This preserves the API/search behavior that the frontend object-tree
registration layout relies on.
## Tests
- `vendor/bin/pest
tests/Unit/Invoicing/InvoicingPeriodRouteGuardsTest.php --colors=always`
Note: local Composer install was run with
`--ignore-platform-req=ext-mysqli --ignore-platform-req=ext-gd` because
those PHP extensions are not enabled in this worker image; the executed
guard test does not use them.
Co-authored-by: Jeppe Bundgaard <jb@truckwash.dk>
