Add contributing guide

Author: ph8n

CONTRIBUTING.md

@@ -0,0 +1,34 @@
+# Contributing
+
+Thanks for helping make `nytgames-cli` better.
+
+## Getting Started
+
+- Install Zig `0.15.1`.
+- Build: `zig build`
+- Run: `zig build run`
+- Tests: `zig build test`
+
+## Conventions
+
+- Keep changes focused and small; avoid unrelated refactors in the same PR.
+- Format Zig code with `zig fmt` on files you touch.
+- Prefer clear, explicit control flow over cleverness.
+- Keep the app cross-platform; guard OS-specific code with `builtin.os.tag`.
+- Avoid adding new dependencies unless there is a strong reason.
+
+## Documentation
+
+- Update `README.md` for user-facing changes.
+- If you change install behavior, update the installer scripts and docs together.
+
+## Commits & PRs
+
+- Use short, imperative commit messages (e.g. "Fix stats date parsing").
+- Include a concise summary of the change and how it was tested.
+- If tests are not run, say why.
+
+## Release Notes (Maintainers)
+
+- Releases are built by GitHub Actions when a tag `vX.Y.Z` is pushed.
+- Packaging and installers are in `.github/workflows/release.yml` and `scripts/`.