Nix improvements

[roninjin10]

• Add direnv feat: nix direnv #1367
• Add to ci/cd
• Update contributing.md
• (nice to have) use in dev container
• (nice to have) might be nice of nx was installed globally in nix

[linear]

TEV-1356 Nix improvements

[shazow]

Re ci/cd: Consider using https://github.com/marketplace/actions/the-determinate-nix-installer, I haven't tried it yet but it's supposed to be very comprehensive and automagically takes care of caching store stuff iirc.

Also related post: https://nix.dev/tutorials/nixos/continuous-integration-github-actions.html

[shazow]

Re docker: Nix can generate docker images, use pkgs.dockerTools.buildLayeredImage, some posts:

https://nix.dev/tutorials/nixos/building-and-running-docker-images.html
https://xeiaso.net/talks/2024/nix-docker-build/

[shazow]

Some other fun features to experiment with:

• Can add app entrypoints so people can nix run the repo, for example something like: nix run github:shazow/foundry.nix#cast -- gas-price
• There's various testing provisions, from simple flake target runners to whole VMs you can spawn and have talk to each other.