Enable reference integration verification CI workflow

> [!IMPORTANT]
> Link the implementing PR to this issue by including `Closes #`
> in the PR description or commit message.

### What

Create `.github/workflows/reference-integration.yml` — a CI workflow that
triggers a smoke test of the Time module in the
[SCORE Reference Integration](https://github.com/eclipse-score/reference_integration)
on every PR, ensuring the module integrates correctly into the full S-CORE
ecosystem before merging.

Based on the pattern from `eclipse-score/lifecycle/.github/workflows/reference-integration.yml`.

Note: the lifecycle version is currently disabled (`if: false`) due to
[eclipse-score/lifecycle#84](https://github.com/eclipse-score/lifecycle/issues/84).
This task should track that upstream fix and enable the workflow once it is resolved.

### Acceptance Criteria

- [ ] `.github/workflows/reference-integration.yml` exists and calls the reusable `eclipse-score/reference_integration/.github/workflows/reusable_smoke-test.yml`
- [ ] Workflow triggers on `pull_request` and `merge_group`
- [ ] `module_name` is set to `score_time` (or the correct BCR name)
- [ ] Upstream blocker (`eclipse-score/lifecycle#84`) is resolved or explicitly tracked as a known dependency

### References

- Parent epic: #108
- Lifecycle reference implementation: `eclipse-score/lifecycle/.github/workflows/reference-integration.yml`
- Upstream blocker: https://github.com/eclipse-score/lifecycle/issues/84