Define Draft Time Module Roadmap to S-CORE v1.0

## What

Define and agree on the initial Time module roadmap that maps out the delivery path
from v0.8 to S-CORE v1.0 — capturing feature scope, artefact maturity targets (L0–L4)
per process area, and the per-component breakdown across all four SW components.

## Background

The S-CORE project requires all modules to align on maturity level targets at each release
gate (v0.8, v0.9, v0.10, v1.0). The Time module enters v0.8 with a focused scope
(reference_integration CI only, #68); process artefact catch-up is planned for v0.9.
A documented plan ensures the team has a shared understanding of what is expected at each
gate and where the known gaps and risks are.

## Deliverable

`docs/release/roadmap.rst` in the module repository, covering:

- Feature scope table (in-scope / deferred)
- Roadmap Overview: artefact × milestone with L0–L4 maturity targets
- Detailed Breakdown: per-component tables for PA2–PA6
- Summary gate compliance table (project requirement vs. Time module delivery)
- Epics & tracking links to GitHub board

Reference: https://eclipse-score.github.io/process_description/main/process_areas/documentation_management/

## Acceptance Criteria

- [ ] Feature scope is explicit: in-scope (SteadyTime, SystemTime, VehicleTime, HighResSteadyTime) and deferred (AbsoluteTime)
- [ ] L0–L4 maturity targets are agreed for each process artefact at each milestone (v0.8–v1.0)
- [ ] `score/time_slave` one-milestone lag is documented
- [ ] SCA/coverage baseline confirmed from current CI (≥ 85% C0)
- [ ] `docs/release/roadmap.rst` merged to main
- [ ] Reviewed and agreed by Time FT team