feat: 4Hz fan control with gear/cruise-aware clamps; move hot signals to cereal

Fan control rework (thermald → 4Hz):
- DT_TRML 0.5s → 0.25s (thermald loop + fan PID now at 4Hz)
- New clamp rules based on (gear, cruise_engaged, standstill):
    parked                                → 0-100%
    in drive + cruise engaged (any speed) → 30-100%
    in drive + cruise off + standstill    → 10-100%
    in drive + cruise off + moving        → 30-100%
- thermald now reads gearShifter (via carState) and controlsState.enabled,
  passes them to fan_controller.update()
- Removed BENCH_MODE special case — new rules cover bench automatically
- Removed ignition-based branches — gear is the correct signal

System health overlay:
- Subscribed UI to peripheralState so we can read fanSpeedRpm
- Added FAN row: actual fan% (RPM / 65) to sit alongside LAG/DROP/TEMP/CPU/MEM.
  Shows the real fan output vs. what the PID is asking for.

Migrate hot signals from paramsMemory to cereal (frogpilotCarControl):
- Added latRequested @3 and noLatLaneChange @4 to FrogPilotCarControl schema
- controlsd sets FPCC.latRequested / FPCC.noLatLaneChange (send-on-change
  already gates the IPC)
- modeld reads from sm['frogpilotCarControl'] (added to its subscribers)
  instead of paramsMemory (saves ~20 file-read syscalls/sec)
- carcontroller reads from frogpilot_variables (set in-process by controlsd)
  instead of paramsMemory (saves ~100 file-read syscalls/sec in 100Hz path).
  Dropped carcontroller's now-unused Params instance and import.
- UI (ui.cc, onroad.cc) reads from sm['frogpilotCarControl'].noLatLaneChange
- Removed LatRequested and no_lat_lane_change param registrations + defaults

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

selfdrive/ui/qt/onroad.cc

@@ -79,9 +79,10 @@ void OnroadWindow::updateState(const UIState &s) {
   nvg->update();  // CLEARPILOT: force repaint every frame for HUD elements
 
   QColor bgColor = bg_colors[s.status];
-  if (paramsMemory.getBool("no_lat_lane_change") == 1) {
+  // CLEARPILOT: read from frogpilotCarControl cereal message (was paramsMemory)
+  if ((*s.sm)["frogpilotCarControl"].getFrogpilotCarControl().getNoLatLaneChange()) {
     bgColor = bg_colors[STATUS_DISENGAGED];
-  } 
+  }
 
   if (bg != bgColor) {
     bg = bgColor;
@@ -753,6 +754,7 @@ void AnnotatedCameraWidget::drawHealthMetrics(QPainter &p) {
   auto cs = sm["controlsState"].getControlsState();
   auto ds = sm["deviceState"].getDeviceState();
   auto mv = sm["modelV2"].getModelV2();
+  auto ps = sm["peripheralState"].getPeripheralState();
 
   float lag_ms = cs.getCumLagMs();
   float drop_pct = mv.getFrameDropPerc();
@@ -760,6 +762,8 @@ void AnnotatedCameraWidget::drawHealthMetrics(QPainter &p) {
   int mem_pct = ds.getMemoryUsagePercent();
   int cpu_pct = 0;
   for (auto v : ds.getCpuUsagePercent()) cpu_pct = std::max(cpu_pct, (int)v);
+  // Actual fan (not commanded): scale RPM to 0-100 using 6500 RPM as full scale
+  int fan_pct = std::min(100, (int)(ps.getFanSpeedRpm() * 100 / 6500));
 
   auto color_for = [](float v, float warn, float crit) {
     if (v >= crit) return QColor(0xff, 0x50, 0x50);   // red
@@ -774,6 +778,7 @@ void AnnotatedCameraWidget::drawHealthMetrics(QPainter &p) {
     {"TEMP", QString::number((int)temp_c),  color_for(temp_c,  75.f,  88.f)},
     {"CPU",  QString::number(cpu_pct),      color_for((float)cpu_pct, 75.f, 90.f)},
     {"MEM",  QString::number(mem_pct),      color_for((float)mem_pct, 70.f, 85.f)},
+    {"FAN",  QString::number(fan_pct),      QColor(0xff, 0xff, 0xff)},
   };
 
   p.save();
@@ -885,7 +890,8 @@ void AnnotatedCameraWidget::drawLaneLines(QPainter &painter, const UIState *s) {
   // paint center lane path
   // QColor bg_colors[CHANGE_LANE_PATH_COLOR];
 
-  bool is_no_lat_lane_change = paramsMemory.getBool("no_lat_lane_change");
+  // CLEARPILOT: read from frogpilotCarControl cereal message (was paramsMemory)
+  bool is_no_lat_lane_change = sm["frogpilotCarControl"].getFrogpilotCarControl().getNoLatLaneChange();
 
   QColor center_lane_color;