- Add packages/opencode with pre-built binaries from GitHub releases (v1.4.0)
- Support all 4 platforms (aarch64-darwin, x86_64-darwin, x86_64-linux, aarch64-linux)
- Add update-opencode flake app for automated version bumps
- Install opencode via home.roles.base so it's available on all machines
- Reformat flake.nix and packages with nixfmt