feat: add minimal Debian image build system with WireGuard-only networking

Add complete build infrastructure for football secure access system:
- Minimal Debian base with only IceWM and Remmina
- WireGuard-only networking with strict firewall (eth0 allows only WireGuard)
- All network traffic routed through mandatory VPN tunnel
- Secure Boot enforced for physical deployments
- Zero remote access - SSH, telnet disabled and blocked
- AppArmor, auditd, and fail2ban for security hardening

Build system generates both VM (qcow2) and physical (raw) images.
WireGuard endpoint IP and port configurable via build script variables.

Includes:
- Package list with minimal dependencies
- System hardening scripts
- WireGuard client and server configuration tools
- Comprehensive documentation (README.md, QUICKSTART.md)
- systemd services for firewall enforcement
- User environment with automatic IceWM startup

💘 Generated with Crush

Assisted-by: GLM-4.7 via Crush <crush@charm.land>

chroot-overlay/home/user/.xinitrc

@@ -0,0 +1,19 @@
+#!/bin/bash
+# ~/.xinitrc - Automatically start IceWM and Remmina
+
+# Set keyboard layout if needed
+setxkbmap us
+
+# Set reasonable defaults for IceWM
+export ICEWM_PRIVCFG=$HOME/.icewm
+
+# Start IceWM
+icewm &
+ICEWM_PID=$!
+
+# Start Remmina (maximized)
+remmina &
+REMMINA_PID=$!
+
+# Wait for IceWM
+wait $ICEWM_PID