Run ruff check --fix: remove unused imports (F401), fix f-strings
without placeholders (F541), remove unused variables (F841), fix
duplicate dict key (F601).
Run isort --profile black: normalize import ordering across all files.
Run ruff format: apply consistent formatting (black-compatible) to
all 58 Python files.
3 intentional E402 remain (imports after require_yaml() must execute
after yaml is available).
all ZIP files (neogeo.zip, pgm.zip, etc.) are rebuilt with fixed
metadata before packing: sorted filenames, epoch timestamps, fixed
permissions, deflate level 9. same ROM atoms = same ZIP hash, always.
115 internal ZIPs verified identical across two independent builds.
enables version-agnostic ZIP assembly from ROM atoms indexed by CRC32.