feat: add ER evaluation

[YongboYu]

Note

Adds a fast, refactored entropic relevance evaluation pipeline with scripts and utilities, generating per-window and summary metrics.

• New pmf_benchmark.metrics.entropic_relevance package: DFGConstructor, BackgroundModel, ER automaton/calculator, and orchestration (er_evaluation.py, run_fast.py) producing CSV/JSON and using caching
• CLI entry run_er_evaluation.py and Hydra runner scripts/run_er_evaluation_hydra.py with config configs/er/er_fast.yaml
• Packaging/tooling: update pyproject.toml to setuptools layout, add dev extras and Ruff config
• Update .gitignore to include project data/results paths and uv.lock
• Remove legacy configs under config/ (base and model/preprocessing YAMLs)

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