feat: add install log and first-boot diagnostics

- Installer: tee all output to /var/log/archipelago-install.log
  on the target disk for post-install debugging
- First boot: oneshot service captures system state 30s after boot:
  services, nginx, LUKS, EFI, SSL, containers, journal errors
- On-demand: sudo archipelago-diagnostics to re-run anytime

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

image-recipe/build-auto-installer-iso.sh

@@ -1838,6 +1838,84 @@ if [ -f /cdrom/99-mesh-radio.rules ]; then
   echo "   Installed mesh radio udev rule"
 fi
 
+# First-boot diagnostics — runs once, captures system state for debugging
+cat > /mnt/target/usr/local/bin/archipelago-diagnostics <<'DIAG'
+#!/bin/bash
+LOG="/var/log/archipelago-first-boot-diagnostics.log"
+echo "=== Archipelago First Boot Diagnostics ===" > "$LOG"
+echo "Date: $(date -u)" >> "$LOG"
+echo "Kernel: $(uname -r)" >> "$LOG"
+echo "Hostname: $(hostname)" >> "$LOG"
+echo "IP: $(hostname -I 2>/dev/null)" >> "$LOG"
+echo "" >> "$LOG"
+
+echo "=== Disk ===" >> "$LOG"
+lsblk -o NAME,SIZE,TYPE,MOUNTPOINT,FSTYPE >> "$LOG" 2>&1
+df -h >> "$LOG" 2>&1
+echo "" >> "$LOG"
+
+echo "=== LUKS ===" >> "$LOG"
+ls -la /dev/mapper/archipelago-data 2>&1 >> "$LOG"
+cryptsetup status archipelago-data >> "$LOG" 2>&1 || echo "No LUKS" >> "$LOG"
+echo "" >> "$LOG"
+
+echo "=== Services ===" >> "$LOG"
+for svc in nginx archipelago archipelago-kiosk archipelago-load-images \
+           archipelago-first-boot-containers archipelago-setup-tor \
+           console-setup; do
+    STATUS=$(systemctl is-active "$svc" 2>/dev/null || echo "inactive")
+    ENABLED=$(systemctl is-enabled "$svc" 2>/dev/null || echo "disabled")
+    printf "  %-40s %s / %s\n" "$svc" "$STATUS" "$ENABLED" >> "$LOG"
+done
+echo "" >> "$LOG"
+
+echo "=== Failed Services ===" >> "$LOG"
+systemctl --failed --no-pager >> "$LOG" 2>&1
+echo "" >> "$LOG"
+
+echo "=== Nginx ===" >> "$LOG"
+nginx -t >> "$LOG" 2>&1
+echo "" >> "$LOG"
+
+echo "=== EFI Boot ===" >> "$LOG"
+ls -laR /boot/efi/EFI/ >> "$LOG" 2>&1
+echo "" >> "$LOG"
+
+echo "=== SSL Cert ===" >> "$LOG"
+ls -la /etc/archipelago/ssl/ >> "$LOG" 2>&1
+echo "" >> "$LOG"
+
+echo "=== Podman ===" >> "$LOG"
+su - archipelago -c "podman ps -a --format '{{.Names}} {{.Status}}'" >> "$LOG" 2>&1
+echo "" >> "$LOG"
+
+echo "=== Memory ===" >> "$LOG"
+free -h >> "$LOG" 2>&1
+echo "" >> "$LOG"
+
+echo "=== Journal Errors (last 50) ===" >> "$LOG"
+journalctl -p err --no-pager -n 50 >> "$LOG" 2>&1
+
+echo "Diagnostics saved to $LOG"
+DIAG
+chmod +x /mnt/target/usr/local/bin/archipelago-diagnostics
+
+cat > /mnt/target/etc/systemd/system/archipelago-diagnostics.service <<'DIAGSVC'
+[Unit]
+Description=Archipelago First Boot Diagnostics
+After=multi-user.target archipelago.service nginx.service
+ConditionPathExists=!/var/log/archipelago-first-boot-diagnostics.log
+
+[Service]
+Type=oneshot
+ExecStartPre=/bin/sleep 30
+ExecStart=/usr/local/bin/archipelago-diagnostics
+RemainAfterExit=yes
+
+[Install]
+WantedBy=multi-user.target
+DIAGSVC
+
 # Ensure SSL cert exists for nginx HTTPS (safety net if rootfs build missed it)
 if [ ! -f /mnt/target/etc/archipelago/ssl/archipelago.crt ]; then
     mkdir -p /mnt/target/etc/archipelago/ssl
@@ -1856,6 +1934,7 @@ chroot /mnt/target systemctl enable archipelago-load-images.service 2>/dev/null
 chroot /mnt/target systemctl enable archipelago-setup-tor.service 2>/dev/null || true
 chroot /mnt/target systemctl enable archipelago-first-boot-containers.service 2>/dev/null || true
 chroot /mnt/target systemctl enable archipelago-kiosk.service 2>/dev/null || true
+chroot /mnt/target systemctl enable archipelago-diagnostics.service 2>/dev/null || true
 
 # Install first-boot diagnostic script — runs once after first boot and logs system state
 cat > /mnt/target/opt/archipelago/scripts/first-boot-diag.sh <<'DIAGSCRIPT'