"Can my Windows teammate join?" got three answers from three official
surfaces: README's feature list said macOS & Linux, its CLI table
documented an HKCU Run entry on Windows, and the hub's Installation page
named no OS at all.
Windows autostart is real code that cannot run — internal/store's flock
and internal/daemon's Kill/Setsid are unix-only, so GOOS=windows does
not build. The fix is the docs, not the port: every Windows claim comes
out of README, web/docs and `bdrive autostart`'s own help, and the
Installation page gains one line naming the supported systems.
No Go source is deleted; internal/autostart/autostart_windows.go stays
compiled-but-dormant for whenever the port happens.
