Fix UEFI snapshot support and ensure sudo privileges

iridium_installer/backend/os_install.py

@@ -190,6 +190,13 @@ UUID={efi_uuid} /boot vfat defaults 0 2
             p = subprocess.Popen(["chroot", mount_root, "chpasswd"], stdin=subprocess.PIPE, text=True)
             p.communicate(input=f"{user_info['username']}:{user_info['password']}")
             
+            # Ensure wheel group has sudo privileges
+            sudoers_dir = os.path.join(mount_root, "etc/sudoers.d")
+            os.makedirs(sudoers_dir, exist_ok=True)
+            with open(os.path.join(sudoers_dir, "wheel"), "w") as f:
+                f.write("%wheel ALL=(ALL) ALL\n")
+            os.chmod(os.path.join(sudoers_dir, "wheel"), 0o440)
+
             # Set hostname
             with open(os.path.join(mount_root, "etc/hostname"), "w") as f:
                 f.write(user_info["hostname"] + "\n")