score/ts_client: Create detailed design (comp_dd_sta)

> [!IMPORTANT]
> Link the implementing PR to this issue by including `Closes #89` in the PR description or commit message.

### What

Write the detailed design document for `score/ts_client`.

Create `score/ts_client/docs/detailed_design/index.rst` using the sphinx-needs `comp_dd_sta` directive. Decompose the component into units, document their responsibilities and interfaces, and connect every unit to requirements (`:implements:`) and architecture (`:satisfies:`).

> **Note**: Create this ticket after [PR #54](https://github.com/eclipse-score/inc_time/pull/54) merges, as it changes the shared memory layer architecture.

Units to cover: `GptpIpcPublisher` (writes gPTP data into shared memory), `GptpIpcReceiver` (reads data from shared memory), `GptpIpcChannel` (shared memory management layer); data format in shared memory.

### Acceptance Criteria

- [ ] `comp_dd_sta` directive in place with `:status: valid`
- [ ] Shared memory protocol (data format, publisher/receiver contract) described
- [ ] `:implements:` and `:satisfies:` links present for every unit
- [ ] `req-Id` traceability comments in source for every traced unit

### References

- [S-CORE Implementation & Detailed Design](https://eclipse-score.github.io/process_description/main/process_areas/implementation/)