Remove unused imports (deque, sys, Opcode, struct, _REPLAY_ADJUSTABLE_OPCODES)
across 4 active Python files and refactor semicolons to separate statements
in radar_protocol.py. Add ruff lint job to CI workflow targeting only the
active files (excludes legacy GUI_V*.py and v7/).
Three parallel jobs covering all AERIS-10 test infrastructure:
- Python dashboard tests (58): protocol, connection, replay, opcodes, e2e
- MCU firmware tests (20): bug regression (15) + Gap-3 safety (5)
- FPGA regression (23 TBs + lint): unit, integration, and system e2e
Triggers on push/PR to main and develop branches.