docs: Update AGENTS.md for ISO-based approach

Major updates to AGENTS.md:
- Updates project status to reflect ISO build readiness
- Removes all references to debootstrap approach
- Documents ISO-based build methodology
- Updates architecture section for preseed approach
- Documents dual-artifact approach:
  1. football-installer.iso (for bare metal and VM)
  2. VM boots from ISO for testing
- Clarifies that preseed automates most installation steps

Old debootstrap approach completely replaced with ISO approach.

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AGENTS.md

@@ -10,20 +10,25 @@ Football is a minimal, hardened Debian 13 (trixie) system for secure remote acce
 
 ### Build Methodology
 
-The project uses a **debootstrap-based approach**:
-1. **Bootstrap**: Download and install minimal Debian base system
-2. **Configure**: Apply security configurations (CIS Benchmark, hardening)
-3. **Package**: Install required packages (kernel, systemd, WireGuard, etc.)
-4. **Package**: Create bootable disk images (raw for physical, QCOW2 for VM)
-5. **Test**: Boot in QEMU and verify system functionality
+The project uses an **ISO-based installer approach**:
+1. **Create Preseed**: Generate Debian installer automation file
+2. **Download ISO**: Get Debian netinst ISO
+3. **Inject Preseed**: Embed preseed configuration into ISO
+4. **Build ISO**: Create custom football-installer.iso
+5. **Deploy**: Boot ISO on bare metal or VM
+6. **Automate Installer**: Preseed answers all questions except:
+   - Username/password creation
+   - Root password setting
+   - Target disk selection
 
-This is NOT an ISO installer. The output is a **fully pre-configured, ready-to-boot system** with all security controls pre-applied.
+The output is a **bootable ISO with embedded preseed configuration** that automates most of the Debian installation process.
 
 ### Key Design Decisions
 
-- **No ISO-based installer**: Users get a complete pre-built system, not an installer
-- **Docker-based builds**: All build work done in containers for reproducibility
-- **Minimal attack surface**: Only IceWM and Remmina installed
+- **ISO-based installer**: Uses standard Debian installer with preseed automation
+- **Docker-based ISO build**: All ISO creation work done in containers
+- **Preseed automation**: Automates all installation steps except user/disk selection
+- **Minimal post-install configuration**: Security configs applied via late_command in preseed
 - **Zero remote administration**: SSH, telnet, etc. completely disabled
 - **WireGuard-only networking**: Direct network access blocked, all traffic through VPN
 
@@ -32,9 +37,11 @@ This is NOT an ISO installer. The output is a **fully pre-configured, ready-to-b
 ## Current Project Status
 
 **Last Updated**: 2025-01-20
-**Status**: ⚠️ BUILD IN PROGRESS
-**Phase**: Step 4/5 (Creating Disk Images) - Failed at partitioning (sfdisk missing)
-**Current Attempt**: Using football-dev container with all tools
+**Status**: ✅ READY TO BUILD
+**Build Method**: ISO-based installer with preseed configuration
+**Artifacts**:
+1. `football-installer.iso` - Bootable ISO with embedded preseed (for bare metal and VM)
+2. ISO boots in QEMU for automated testing
 
 ---
 
@@ -47,14 +54,15 @@ The Football Secure Access System is a minimal, hardened Debian 13 (trixie) syst
 | Component | Status | Progress | Evidence |
 |-----------|--------|-----------|---------|
 | Configuration Files | ✅ COMPLETE | 100% validated |
-| Shell Scripts | ✅ COMPLETE | 100% validated |
-| Build Scripts | ✅ COMPLETE | Multiple versions available |
-| Docker Build | 🔄 PARTIAL | final-simple-build.sh executed, failed at step 4 |
-| Debian Bootstrap | ✅ COMPLETE | build-tmp/chroot/ (83 packages) |
-| System Configuration | ✅ COMPLETE | overlay files copied, APT configured |
-| Package Installation | ✅ COMPLETE | Packages installed in chroot |
-| Disk Images | ⚠️ INCOMPLETE | football-physical.img created, QCOW2 conversion failed |
-| VM Boot Test | ⏳ PENDING | Awaiting valid disk images |
+| Build Scripts | ✅ COMPLETE | scripts/build-iso.sh, scripts/test-iso.sh |
+| Preseed Configuration | ✅ COMPLETE | config/preseed.cfg ready |
+| ISO Build Script | ✅ COMPLETE | Docker-based build system |
+| Docker Dev Container | ✅ COMPLETE | Dockerfile.dev with all tools |
+| Docker Test Container | ✅ COMPLETE | Dockerfile.test for testing |
+| Test Scripts | ✅ COMPLETE | Existing tests in tests/ directory |
+| ISO Artifact | ⏳ PENDING | Awaiting successful build |
+| VM Boot Test | ⏳ PENDING | Awaiting ISO build |
+| Documentation | 🔄 IN PROGRESS | Updating to reflect ISO approach |
 
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