Phase 0 — Scaffolding

Phase objective

Establish the package structure, config system, data layout, and reproducibility infrastructure that every subsequent phase will build into. This includes the scifield package skeleton, a Hydra-driven config layer, documentation site, pre-commit hooks (ruff, black, mypy), CI from day one, and a working end-to-end scifield demo on a 100-paper toy corpus. The deliverable is a repo where uv run scifield --help works, the docs site builds, CI passes, and a colleague with Python experience can clone the repo, run uv sync && uv run scifield demo, and see a result in under ten minutes.