nanobot's Windows exec environment was not forwarding ProgramFiles and related variables, so docker desktop start could not discover the desktop CLI plugin and reported unknown command. Forward the missing variables and add a regression test that covers the Windows env shape.
ExecTool hardcoded bash, breaking exec on Windows. Now uses cmd.exe
via COMSPEC on Windows with a curated minimal env (PATH, SYSTEMROOT,
etc.) that excludes secrets. bwrap sandbox gracefully skips on Windows.
