#983 ruff 0.16.4: engine 28 and jumper 31 findings fail their CI lint; superproject 45 held by a ratchet; format drift in all three

EARS: ruff check and ruff format --check at the version in uv.lock shall report zero findings in highway, highway-engine and jumper. Measured by #918 (ruff 0.16.4, the version uv.lock pins): - superproject (docker/highway-core excluded): 45 findings in 24 files (33 RUF100 unused noqa, 10 PLR0917, 8 ISC004, ...). Held at that count per file by scripts/ci/ratchet.py and scripts/ci/ruff_baseline.json; a new finding fails the lint job. - engine (own pyproject config): 28 findings (14 RUF100, 6 I001, 3 SIM117, 2 PIE810, 2 RET501, 1 UP035); the engine lint job runs plain ruff check and is red until these are fixed (24 are auto-fixable). - jumper (no ruff config, ruff defaults): 31 findings (9 UP017, 8 I001, 6 BLE001, 4 RUF059, 2 S110, 1 B018, 1 EXE001); the jumper check job is red until fixed or a ruff config is added. - ruff format --check: superproject 37 files, engine 28, jumper 8 would be reformatted. No format gate exists yet; add it once a repo is clean.