fix: resolve ruff lint errors and add lint CI job

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/).

9_Firmware/9_3_GUI/smoke_test.py

@@ -27,7 +27,6 @@ Exit codes:
 import sys
 import os
 import time
-import struct
 import argparse
 import logging