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>

common/params.cc

@@ -217,6 +217,7 @@ std::unordered_map<std::string, uint32_t> keys = {
 
     // FrogPilot parameters
     {"AccelerationPath", PERSISTENT},
+    {"BenchCruiseActive", CLEAR_ON_MANAGER_START},
     {"BenchCruiseSpeed", CLEAR_ON_MANAGER_START},
     {"ClpUiState", CLEAR_ON_MANAGER_START},
     {"BenchEngaged", CLEAR_ON_MANAGER_START},
@@ -257,6 +258,8 @@ std::unordered_map<std::string, uint32_t> keys = {
     {"ClearpilotHasSpeed", PERSISTENT},
     {"ClearpilotIsMetric", PERSISTENT},
     {"ClearpilotSpeedUnit", PERSISTENT},
+    {"ClearpilotCruiseWarning", PERSISTENT},
+    {"ClearpilotCruiseWarningSpeed", PERSISTENT},
 
     // {"SpeedLimitLatDesired", PERSISTENT},
     // {"SpeedLimitVTSC", PERSISTENT},