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/thermald/thermald.py

@@ -292,8 +292,18 @@ def thermald_thread(end_event, hw_queue) -> None:
     msg.deviceState.maxTempC = all_comp_temp
 
     if fan_controller is not None:
-      standstill = sm['carState'].standstill if sm.seen['carState'] else False
-      msg.deviceState.fanSpeedPercentDesired = fan_controller.update(all_comp_temp, onroad_conditions["ignition"], standstill)
+      # CLEARPILOT: fan rules based on gear (parked vs drive) and cruise-engaged state
+      if sm.seen['carState']:
+        cs = sm['carState']
+        standstill = cs.standstill
+        is_parked = cs.gearShifter == log.CarState.GearShifter.park
+      else:
+        standstill = False
+        is_parked = True  # default safe: assume parked, no fan floor
+      cruise_engaged = sm['controlsState'].enabled if sm.seen['controlsState'] else False
+      msg.deviceState.fanSpeedPercentDesired = fan_controller.update(
+        all_comp_temp, onroad_conditions["ignition"], standstill,
+        is_parked=is_parked, cruise_engaged=cruise_engaged)
 
     is_offroad_for_5_min = (started_ts is None) and ((not started_seen) or (off_ts is None) or (time.monotonic() - off_ts > 60 * 5))
     if is_offroad_for_5_min and offroad_comp_temp > OFFROAD_DANGER_TEMP:
@@ -422,10 +432,10 @@ def thermald_thread(end_event, hw_queue) -> None:
     if power_monitor.should_shutdown(onroad_conditions["ignition"], in_car, off_ts, started_seen):
       cloudlog.warning(f"shutting device down, offroad since {off_ts}")
       # CLEARPILOT: signal dashcamd to close recording gracefully before power-off
-      params.put_bool("DashcamShutdown", True)
+      params_memory.put_bool("DashcamShutdown", True)
       deadline = time.monotonic() + 15.0
       while time.monotonic() < deadline:
-        if not params.get_bool("DashcamShutdown"):
+        if not params_memory.get_bool("DashcamShutdown"):
           cloudlog.info("dashcamd shutdown ack received")
           break
         time.sleep(0.5)