fix(installer): add logging to guided installer and fix NVMe partition naming

- Add full session logging (tee to logfile) to archbaseos-guided-install.sh,
  matching the pattern already in arch-autoinstall.sh; copy log to /mnt/boot/
  at the end so it survives into the new system
- Add part() helper to both installers so NVMe/eMMC drives use the correct
  'p' separator (e.g. /dev/nvme0n1p1 instead of the broken /dev/nvme0n11)
- Add disk size guard to arch-autoinstall.sh: fail early with a clear message
  if ROOT_GIB would be < 8GiB instead of passing a nonsense value to parted

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

setup/arch-autoinstall.sh

@@ -49,6 +49,8 @@ get_mac_suffix() {
     printf '%s' "${mac//:/}"
 }
 
+part() { [[ "$1" == *nvme* || "$1" == *mmcblk* ]] && echo "${1}p${2}" || echo "${1}${2}"; }
+
 if $AF_MODE; then
     echo "Answerfile detected: $ANSWERFILE"
     # Ensure jq is available
@@ -165,6 +167,10 @@ SWAP_SIZE="${RAM_GB}GiB"
 DISK_SIZE=$(lsblk -b -dn -o SIZE "$DRIVE")
 DISK_GIB=$((DISK_SIZE / 1024 / 1024 / 1024))
 ROOT_GIB=$((DISK_GIB - RAM_GB - 15))
+if (( ROOT_GIB < 8 )); then
+    echo "ERROR: Not enough disk space. Root would be only ${ROOT_GIB}GiB (need ≥8GiB)."
+    exit 1
+fi
 
 echo "Partition plan:"
 echo "  Boot: ${BOOT_SIZE}"
@@ -180,9 +186,9 @@ parted "$DRIVE" --script mklabel gpt \
     mkpart ROOT 15GiB "$((15 + ROOT_GIB))"GiB \
     mkpart SWAP "$((15 + ROOT_GIB))"GiB 100%
 
-BOOT_PART="${DRIVE}1"
-ROOT_PART="${DRIVE}2"
-SWAP_PART="${DRIVE}3"
+BOOT_PART=$(part "$DRIVE" 1)
+ROOT_PART=$(part "$DRIVE" 2)
+SWAP_PART=$(part "$DRIVE" 3)
 
 ############################################
 # FORMAT BOOT + SWAP

setup/archbaseos-guided-install.sh

@@ -6,6 +6,19 @@
 
 set -euo pipefail
 
+############################################
+# LOGGING
+############################################
+LOGFILE="$HOME/archbaseos-guided-install.log"
+{
+    echo
+    echo "############################################"
+    echo " Arch Guided Install Log - Started $(date)"
+    echo "############################################"
+    echo
+} >> "$LOGFILE"
+exec > >(tee -a "$LOGFILE") 2>&1
+
 ############################################
 # Helper Functions
 ############################################
@@ -27,6 +40,10 @@ pause() {
     read -rp "Press ENTER to continue..."
 }
 
+# Returns the correct partition device for a given drive and partition number.
+# NVMe and eMMC use a 'p' separator (e.g. /dev/nvme0n1p1), others don't.
+part() { [[ "$1" == *nvme* || "$1" == *mmcblk* ]] && echo "${1}p${2}" || echo "${1}${2}"; }
+
 ############################################
 # ANSWERFILE
 ############################################
@@ -157,9 +174,9 @@ parted -s "$DRIVE" mklabel gpt \
     mkpart ROOT "${EFI_SIZE}GiB" "$((EFI_SIZE + ROOT_SIZE))GiB" \
     mkpart SWAP "$((EFI_SIZE + ROOT_SIZE))GiB" 100%
 
-EFI_PART="${DRIVE}1"
-ROOT_PART="${DRIVE}2"
-SWAP_PART="${DRIVE}3"
+EFI_PART=$(part "$DRIVE" 1)
+ROOT_PART=$(part "$DRIVE" 2)
+SWAP_PART=$(part "$DRIVE" 3)
 
 mkfs.fat -F32 "$EFI_PART"
 mkswap "$SWAP_PART"
@@ -359,7 +376,9 @@ if $AF_MODE && [[ -f /mnt/answerfile.json ]]; then
     rm -f /mnt/answerfile.json
 fi
 
-echo "Installation complete!"
+cp "$LOGFILE" /mnt/boot/ 2>/dev/null || true
+
+echo "Installation complete! Log saved to /mnt/boot/$(basename "$LOGFILE")"
 echo "  umount -R /mnt && reboot"
 if [[ "${_DO_TUI^^}" != "YES" ]]; then
     echo