feat: cruise warning signs and speed limit sign sizing

Cruise warning sign appears above speed limit sign when cruise set
speed is too far from the speed limit:
- Red (over): cruise >= limit + 10 (if limit >= 50) or + 5 (if < 50)
- Green (under): cruise <= limit - 5
- Only when cruise active (not paused/disabled) and limit >= 20
- Nightrider mode: colored text/border on black background

Speed limit sign enlarged 5%. 20px gap between signs. Bench mode
gains cruiseactive command (0=disabled, 1=active, 2=paused).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

selfdrive/clearpilot/bench_cmd.py

@@ -7,6 +7,7 @@ Usage:
   python3 -m selfdrive.clearpilot.bench_cmd speed 20
   python3 -m selfdrive.clearpilot.bench_cmd speedlimit 45
   python3 -m selfdrive.clearpilot.bench_cmd cruise 55
+  python3 -m selfdrive.clearpilot.bench_cmd cruiseactive 0|1|2  (0=disabled, 1=active, 2=paused)
   python3 -m selfdrive.clearpilot.bench_cmd engaged 1
   python3 -m selfdrive.clearpilot.bench_cmd debugbutton       (simulate LKAS debug button press)
   python3 -m selfdrive.clearpilot.bench_cmd dump
@@ -89,6 +90,7 @@ def main():
     "speed": "BenchSpeed",
     "speedlimit": "BenchSpeedLimit",
     "cruise": "BenchCruiseSpeed",
+    "cruiseactive": "BenchCruiseActive",
     "engaged": "BenchEngaged",
   }