Add detailed README covering:
- What this is (ALARM + ES-DE for H700)
- Prerequisites (podman, qemu-user-static, sgdisk, guestfish, make, wget, unzip)
- Build instructions (make FACTORY_IMAGE=path/to/factory.img)
- Default credentials (emulation/emulation)
- How to add ROMs (mount data partition or second SD)
- How to add BIOS files
- How to connect WiFi (nmtui via SSH)
- Partition layout and troubleshooting
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>