This commit introduces the new 'dev-nix' Ansible role, which installs the
Nix package manager in a secure and reproducible way using a locally stored,
SHA256-verified installer script.
Key features:
- Local pinned installer (no network download during execution)
- SHA256 checksum validation to prevent execution of modified installers
- Multi-user (daemon) installation mode
- Optional shell integration via /etc/profile.d
- Fully idempotent, distro-agnostic design
This role matches the structure and conventions of existing dev-* roles
in the Infinito.Nexus ecosystem.
https://chatgpt.com/share/69387c73-bf3c-800f-abcd-c5e7d3717059
