Update documentation safety classification

### What

Update documentation to specify ASIL integrity levels for time module components.

**Scope:** User manual and component requirements documents.

**Proposed defaults:**
- score/time FFI: ASIL-B (TBC pending #33)
- TimeDaemon: ASIL-B
- TimeSlave: QM

### Acceptance Criteria (DoD)

- [ ] User manual has correct safety classifications without (TBC)
- [ ] Component requirements are updated to match decided safety classification

### How

1. **User manual updates**: Update ``docs/manuals/user_manual.rst`` "Safety and Security" section with decided safety classificaitons
2. **Component requirement updates**: Update all component requirements for the components in time to match the decided levels.