- Add a neutral `dms auth sync` command and reuse the shared auth flow from:
- Settings auth toggle auto-apply
- `dms greeter sync`
- `dms greeter install`
- greeter auth cleanup paths
- Rework lockscreen PAM so DMS builds /etc/pam.d/dankshell from the system login stack, but removes fingerprint and U2F from that password path. Keep /etc/pam.d/dankshell-u2f separate.
- Preserve custom PAM files in place to avoid adding duplicate greeter auth when the distro already provides it, and keep NixOS on the non-writing path.
- Split auth capability state by lock screen and greeter
- Share detection between settings UI and lock runtime
- Broaden greeter PAM include detection across supported distros