Fixes#13625
---
> [!NOTE]
> Ensure `reserved_quantity` is adjusted when deleting reservation items via `deleteReservationItems`, with new integration tests covering deletion and inventory updates.
>
> - **Inventory Module Service (`packages/modules/inventory/src/services/inventory-module.ts`)**:
> - Add `deleteReservationItems` API (and transactional `_` variant) that hard-deletes reservations, then updates related inventory levels via `adjustInventoryLevelsForReservationsDeletion`.
> - Wire through event emission/manager decorators consistent with existing patterns.
> - **Integration Tests (`packages/modules/inventory/integration-tests/__tests__/inventory-module-service.spec.ts`)**:
> - Add tests for `deleteReservationItems` to verify deletion by id and `reserved_quantity` adjustments on inventory levels.
> - Minor import update to include `ReservationItemDTO`.
> - **Changeset**:
> - Patch release note for `@medusajs/inventory` documenting the fix.
>
> <sup>Written by [Cursor Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit ac6641a9ec9543115504407f708f81bd427c3444. This will update automatically on new commits. Configure [here](https://cursor.com/dashboard?tab=bugbot).</sup>
FIXES SUP-1824
**What**
The medusa internal service update should always return the data in the expected shape described by the interface. The medusa service should not have to handle the reshapre
**What**
First iteration to prevent events from overwhelming the systems.
- Group emitted event ids when possible instead of creating a message per id which leads to reduced amount of events to process massively in cases of import for example
- Update the index engine to process event data in batches of 100
- Update event handling by the index engine to be able to upsert by batch as well
- Fix index engine build config for intermediate listeners inferrence
