roadmap-v2.6.0

Added

• A phase's artefact key names where its HTML dashboard is written, as a path relative to the project root. render and recompute --render share one resolver: --out, then the key, then docs/artefacts/roadmap-{slug}.html. Without the key every existing roadmap behaves as before.
• roadmap.py config artefact PATH [--phase NAME] writes the key in field order without touching anything else, and --clear removes it. An absolute path, a .. segment or a non-.html suffix is refused; validate reports a hand-edited one as a discrepancy and render refuses to write it.
• roadmap:configure artefact <path>|clear [phase] runs config and then one render, so the file exists at the new path before the skill reports.
• render --phase and config --phase accept an archived phase, so its dashboard can be regenerated or re-homed. ready, recompute and claim still see active phases only.

Fixed

• recompute --render wrote to the slug path even when a project's dashboard lived elsewhere, and reported no artefact.