Add Tenstorrent Blackhole support

[peterschmidt85]

Summary:

• Add shim detection and normalization for Tenstorrent Blackhole boards, including Galaxy and PCIe fixtures.
• Add Tenstorrent Blackhole and existing Tenstorrent resource validation coverage.
• Update Tenstorrent docs, SSH fleet requirements, Protips, troubleshooting, and mkdocs nav.

Dependency:

• Depends on [Tenstorrent] Support Blackhole accelerators gpuhunt#232. pyproject.toml temporarily points gpuhunt to that PR; the TODO comment tracks restoring the PyPI source after release.