Host Hardening: SSSD and PAM (stub)

This guide will cover:

• Generating /etc/sssd/sssd.conf templates for LDAP/AD integration
• Configuring nsswitch.conf for passwd, group, and shadow lookups via SSSD
• Setting up the PAM stack (pam_unix.so sufficient + pam_sss.so use_first_pass)
• Hardening host configuration for air-gap deployments