Define Manager with Set/Status in autostart.go; add concrete types
(windowsManager, linuxManager, otherManager) in the per-platform files.
Service gains a manager field wired by Open() via autostart.New();
AutostartStatus and ApplyAutostart delegate to it instead of calling
package-level functions directly. Tests that don't need autostart get a
nil manager, which is safe (no-op returns).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
mixeme
428f018fe1