NixOS-based AC Native OS for broad hardware support via modular kernel + linux-firmware. Adds "nix" variant to the oven build pipeline: - fedac/nixos/: NixOS flake with configuration, kiosk module (cage + ac-native), hardware module (GPU/WiFi/audio firmware), WiFi module, and ac-native Nix package derivation (confirmed compiling) - oven: native-builder.mjs gains "nix" variant that runs `nix build` directly on host (no Docker), uploads ISO with nix- channel prefix - oven: git poller watches fedac/nixos/ alongside fedac/native/ - oven: deploy.sh installs Nix + enables flakes + GC timer - ac-os: adds `nixos` subcommand (build/flash/upload/pull) - upload-release.sh: ISO-only mode now uploads version + sha256 files Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>