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/.bashrc

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+# ~/.bashrc - Football secure access system
+# This script automatically starts IceWM and Remmina
+
+# Start X with IceWM on login
+if [ -z "$DISPLAY" ] && [ "$XDG_VTNR" = "1" ]; then
+    exec startx
+fi
+
+# Security aliases
+alias rm='rm -i'
+alias cp='cp -i'
+alias mv='mv -i'
+
+# PATH additions
+export PATH=$PATH:/usr/local/bin
+
+# Display security notice on login
+echo ""
+echo "================================================================"
+echo "  FOOTBALL - SECURE ACCESS SYSTEM"
+echo "================================================================"
+echo "  Remote access to this system is DISABLED."
+echo "  Local console access only."
+echo "  System is automatically starting IceWM + Remmina."
+echo "================================================================"
+echo ""

chroot-overlay/home/user/.icewm/preferences

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+# IceWM configuration for football system
+
+# Window placement
+TaskBarShowClock=1
+TaskBarShowStartMenu=1
+TaskBarShowWindowListMenu=1
+TaskBarShowWorkspaces=0
+TaskBarShowWindows=0
+
+# Auto-start Remmina
+StartupCommand="remmina"
+
+# No desktop icons (clean interface)
+DesktopBackgroundCenter=1
+DesktopBackgroundColor="rgb:00/33/66"
+
+# Security - minimize features
+ShowLoginStatus=0
+ShowLogoutMenu=1
+ShowSettingsMenu=0
+ShowHelpMenu=0
+ShowRunProgram=0
+
+# Remmina should be main focus
+ClickToFocus=1
+FocusOnAppRaise=1
+RaiseOnFocus=1

chroot-overlay/home/user/.xinitrc

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+#!/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

chroot-overlay/home/user/Desktop/README.txt

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+# Football Secure Access System
+
+This system is configured for secure access to remote privileged access workstations through a WireGuard VPN tunnel.
+
+**SYSTEM CHARACTERISTICS:**
+- Remote access: DISABLED (no SSH, no network services)
+- Local console access only
+- Automatic IceWM window manager startup
+- Remmina remote desktop client
+- Secure Boot enforced
+- **ALL network traffic MUST go through WireGuard VPN**
+- **Direct network access BLOCKED - only WireGuard allowed**
+
+**NETWORK CONFIGURATION:**
+- Physical interface (eth0): ONLY allows WireGuard to configured endpoint
+- WireGuard tunnel (wg0): ALL outbound traffic goes through this tunnel
+- Inbound traffic: BLOCKED (except WireGuard keepalives)
+- DHCP: Allowed on eth0 only for initial IP acquisition
+
+**USAGE:**
+1. Login with local user account
+2. IceWM and Remmina start automatically
+3. WireGuard tunnel is established automatically
+4. Use Remmina to connect to PAW (Privileged Access Workstation) through VPN
+5. Close Remmina when done
+6. System locks automatically on inactivity
+
+**SECURITY:**
+- No remote administration permitted
+- All direct network connections blocked
+- Only WireGuard tunnel traffic allowed to configured endpoint
+- System logs all actions
+- Secure Boot verifies kernel integrity
+- Firewall strictly enforced
+
+**WIREGUARD ENDPOINT:**
+- Configured during build (see build script variables)
+- Only endpoint allowed: WG_ENDPOINT_IP:WG_ENDPOINT_PORT
+- All traffic routes through VPN after connection
+
+**CONTACT:**
+For system issues, contact infrastructure security team.