Repo restructured into python/, powershell/ and linux/. Adds a Windows
PowerShell reference client (5.1 and 7 launchers over one shared
implementation) and a systemd unit for the Python daemon.

Breaking for existing deployments: the Python client moved to python/,
and config.toml moves with it. See README.md.

Fixes found by running it on the real nodes: dosemu subprocess paths
resolved to absolute, TERM pinned so dosemu starts under systemd,
nodes.dat HOST routing lines parsed, and maintenance failures now report
why rather than just an exit code.