feat(01-04): add CLI entry point with setup and info commands

- Create click-based CLI with command group (--config, --verbose options)
- Add 'info' command displaying pipeline version, config hash, data source versions
- Add 'setup' command orchestrating full infrastructure flow:
  - Load config -> create store/provenance
  - Fetch gene universe (with checkpoint-restart)
  - Map Ensembl IDs to HGNC + UniProt
  - Validate mapping quality gates
  - Save to DuckDB with provenance sidecar
- Update pyproject.toml entry point to usher_pipeline.cli.main:cli
- Add .gitignore for data/, *.duckdb, build artifacts, provenance files

.gitignore

@@ -0,0 +1,40 @@
+# Data files
+data/
+
+# DuckDB
+*.duckdb
+*.duckdb.wal
+
+# Python
+__pycache__/
+*.pyc
+*.pyo
+*.pyd
+.Python
+*.so
+*.egg
+*.egg-info/
+dist/
+build/
+.eggs/
+
+# Testing
+.pytest_cache/
+.coverage
+htmlcov/
+.tox/
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+
+# Provenance files (not in data/)
+/*.provenance.json
+
+# Virtual environment
+.venv/
+venv/
+env/