Support unattended installs in omarchy-iso-boot

[gosuwachu]

Summary

• add --cidata-dir to package configurator files into a CIDATA FAT image and attach it to QEMU
• create or reuse a dedicated VM SSH identity, inject its public key, and print ready-to-use SSH and SCP commands
• validate required cidata inputs while preserving supported optional provisioning files
• document the unattended VM boot flow

Depends on #153.

Testing

• ./test/all

[Chessing234]

cidata copy uses a known-file whitelist, ssh key checks are sane, temp dir cleanup on exit.