Improvement: Add Component Integration Tests (CIT) for time_daemon/time_slave and Module Integration Tests (MIT)

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Purpose
- `time_daemon` and `time_slave` currently only have unit tests; component-level and cross-component integration test coverage is missing
- CIT verifies end-to-end component behavior: state-machine transitions, I/O boundary conditions, error-handling paths
- MIT verifies the cross-component data path: `time_slave` → shared memory IPC → `time_daemon`
- Establishing CIT/MIT infrastructure enables future feature scenarios to be added with low friction

Scope
- **time_daemon CIT** — C++ scenarios + Python pytest
- **time_slave CIT** — gPTP protocol stack component tests
- **MIT (Feature Integration Tests)** — cross-component tests
- **Infrastructure**

Out of Scope
- Additional unit tests (UT) — tracked separately
- Requirement-traceability decorators
- End-to-end tests on real hardware / PHC clock — requires hardware environment

Deliverables
- This Improvement introduces a complete **Component Integration Test (CIT)** and **Module Integration Test (MIT)** suite for the `score_time` module, built on the Eclipse SCORE `score_test_scenarios` framework (v0.3.0). It covers both components (`time_daemon`, `time_slave`) and the gPTP shared-memory IPC pipeline between them.

Acceptance criteria
- Test specification and implementation exist. Test passes.