Adds a minimal Makefile wrapping the toolchain the way sneak's other
repos expose it:
- fmt gofmt -w plus prettier (4-space tabs, proseWrap: always)
- fmt-check fail if any Go or Markdown file is unformatted
- lint golangci-lint run ./...
- test go test ./...
- check fmt-check + lint + test (the local pre-commit gate)
Running make fmt normalizes the four existing Markdown docs to the
shared prettier style (80-column proseWrap: always, aligned tables) —
a one-time reflow with no content change. The repo remains exempt from
the rest of the policy scaffold (no Dockerfile, CI, or REPO_POLICIES).
