feat: add Homebrew, Nix, and CI workflows for release automation

[Gutem]

Summary

Add Homebrew formula, Nix flake, and automated CI workflows for multi-platform releases.

Features

🍺 Homebrew Support

• Formula: Formula/dz6.rb — Supports macOS (Intel/ARM) and Linux x64
• Auto-update: Workflow automatically updates SHA256 checksums on release
  Installation (after merge):

brew tap mentebinaria/dz6
brew install dz6

❄️ NixOS Support

• Flake: flake.nix — Build from source with Rust 2024 edition
  Usage:

nix run github:mentebinaria/dz6
nix profile install github:mentebinaria/dz6

🔄 CI Workflows

1. test-release.yml — Tests builds on every PR across macOS, Linux, Windows
2. update-homebrew.yml — Auto-updates formula SHA256 checksums on release
3. publish-nix.yml — Auto-updates flake version on release

Testing

All workflows tested and verified on fork (Gutem/dz6):

• ✅ Test release builds pass on all platforms
• ✅ Cargo-dist release created successfully
• ✅ Binary artifacts built and tested
• ✅ Homebrew formula structure validated

What the Repo Owner Needs to Do

After Merge

Create a release by tagging the version already in Cargo.toml:

git checkout main
git pull origin main
git tag v0.7.0
git push origin v0.7.0

This will automatically:

1. Build binaries for all platforms via cargo-dist
2. Create GitHub Release with artifacts
3. Trigger Homebrew formula update PR
4. Trigger Nix flake update PR

For Future Releases

Just tag and push:

git tag v0.8.0 && git push origin v0.8.0

Everything else is automated.
Closes #18

[merces]

Not a CI expert here but this would only check if the binaries run and emit the version number, right? I think it is safe to assume they will run if compilation was successful, isn't it? I mean, maybe we'll using computational resources for tests that'd never fail. What do you think?

[Gutem]

Did it to test the compiling on ARM and RISC-V archs.
But, as you said, we can take it off

[merces]

This is nice. I haven't thought of hosting the formula myself. But just curious, do you think it's too difficult to get the formula accepted at the offical Homebrew repo? If you have time/interest, could you try to do it?

[Gutem]

Already did some brew contribs in the past, but not entire hosted the repos per se.
Can assume it from now on

[merces]

Something missing here?

[Gutem]

Related to ARM and RISC-v building. Can skip

[merces]

Thanks for your PR! I have a few questions/comments. :)