Refactored helpers to reduce duplication and improve naming.

- Renamed chroot_install/chroot_enable to chroot_pacman_install/chroot_systemd_enable.
- Made chroot_systemd_enable auto-print status, removing need for wrapper functions.
- Used generic prompt helpers instead of duplicating logic in specialized functions.
- Inlined and removed single-use wrapper functions throughout.

lib/system/user.sh

@@ -22,14 +22,10 @@
 # Sets:
 #   USERNAME - the entered username
 prompt_username() {
-    local username
-
     while true; do
-        print "Please enter the username you'd like to use for your account:"
-        read -r username
+        prompt "Please enter the username you'd like to use for your account:" USERNAME
 
-        if validate_username "$username"; then
-            USERNAME="$username"
+        if validate_username "$USERNAME"; then
             return 0
         fi