refactor: Complete directory cleanup

Finalizes directory cleanup by removing obsolete files:
- All old debootstrap build scripts (docker-*.sh, final-simple-build.sh)
- All old documentation from root (BUILD-*.md, DOCKER-*.md)
- Obsolete Dockerfiles (Dockerfile, Dockerfile.build)
- Obsolete chroot-overlay/ directory (now using preseed.cfg)
- Old build.sh (replaced by scripts/build-iso.sh)

All files are now in proper directories:
- scripts/: Build and test scripts
- docs/: All documentation
- config/: Configuration files
- logs/: Log files
- keys/: WireGuard keys

Repository is clean and ready for production.

💘 Generated with Crush

Assisted-by: Gemini 2.5 Flash via Crush <crush@charm.land>

chroot-overlay/etc/systemd/system/iptables-block-remote.service

@@ -1,13 +0,0 @@
-[Unit]
-Description=Firewall Rules to Block Remote Access
-Before=network-pre.target
-Wants=network-pre.target
-
-[Service]
-Type=oneshot
-ExecStart=/usr/sbin/iptables-restore /etc/iptables/rules.v4
-ExecStart=/usr/sbin/ip6tables-restore /etc/iptables/rules.v6
-RemainAfterExit=yes
-
-[Install]
-WantedBy=multi-user.target