CI's lint job ran ruff check but never ruff format --check, letting format drift land silently (79 files had drifted from the pinned ruff 0.15.1). Add the ruff format --check step to ci.yml, reformat the 79 drifted files with the pinned ruff (mechanical only — verified AST-identical to before across all files, no logic changes), and add a Makefile whose test target mirrors the actual CI lane.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
