Replace department-portal allocation summary with the shared allocation-utilization service

## Background

PR #654 adds an Allocation card to the Department Portal. The card currently uses `app/logic/allocation_utilization.py` as a temporary local calculation layer while the official shared allocation-utilization service is being developed.

## Work needed

- Replace the calculations in `app/logic/allocation_utilization.py` with calls to the official shared service.
- Preserve the values required by the Department Portal: total allocated positions, usage by primary/secondary hour bucket, total used positions, and break hours used.
- Confirm which Labor Status Forms should count as used.
- Add or update integration tests.

## Acceptance criteria

- The Department Portal does not contain its own allocation-utilization query logic.
- `allocation_utilization.py` delegates to the official shared service.
- The Allocation card displays correct values for the open term.
- Tests cover the shared-service integration.

## Related work

- Parent feature: PR #654
- Temporary implementation: `app/logic/allocation_utilization.py`