v0.8.1

Per-role elevation tasks with an argv args-file contract: roles the GUI starts on Windows run elevated (Task Manager / installer input works). Task creation rides the install and self-heals from the GUI for admin users. Fixes the v0.8.0 elevation model, whose task XML value was rejected by schtasks (RunLevel must be HighestAvailable in XML — the /RL HIGHEST CLI equivalent), which silently degraded every elevated spawn to non-elevated.