Fix: Update password commands for Pi-hole v6 compatibility

- Use 'pihole setpassword' for v6, fallback to '-a -p' for legacy
- Update management script with v6 password syntax
- Update README with v6 commands
- Tested successfully on Rocky Linux 10.1

README.md

@@ -75,6 +75,10 @@ curl ... | sudo bash -s -- --unattended --dns1 9.9.9.9 --dns2 149.112.112.112
 ### Set Admin Password
 
 ```bash
+# Pi-hole v6+
+pihole setpassword
+
+# Pi-hole v5 (legacy)
 pihole -a -p
 ```
 
@@ -185,7 +189,7 @@ journalctl -u pihole-FTL -f        # Systemd journal
 ### Reset admin password
 
 ```bash
-pihole -a -p
+pihole setpassword
 ```
 
 ## Uninstall