controlsd: suppress freq-only cascade; modeld: variable rate w/ republish cache

- commIssue now fires only on real comms failure (not_alive or CAN RX
  timeout), not on self-declared valid=False cascades from MSGQ-conflate +
  slow-polling freq_ok artifacts. Car drives fine through these and the
  banner was false-positive.
- Add 5-cycle hysteresis (50ms) on commIssue / posenetInvalid /
  locationdTemporaryError / paramsdTemporaryError.
- Cascade-aware suppression: skip posenet/locationd/paramsd temporary
  errors when the only problem is freq_only_cascade (all alive, just
  freq/valid tripped).
- Remove debug _dbg_dump_alert_triggers helper and EVENTS/EVENT_NAME
  imports.
- Re-enable variable-rate modeld (4/10fps idle, 20fps when lat_active /
  lane_changing / calibrating) with republish caching so consumers get
  constant publish rate.
- Split lat_requested (modeld signal) from lat_engaged (actuator gate).
  Momentary steerFaultTemporary no longer drops modeld rate, preventing
  stale-prediction feedback loop on MDPS recovery. CC.latActive still
  respects the fault.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

selfdrive/modeld/modeld.py

@@ -246,19 +246,19 @@ def main(demo=False):
 
     sm.update(0)
 
-    # CLEARPILOT: reverted to two modes only — constant 20fps while moving, standby at
-    # standstill. Variable-rate (4/10fps) caused downstream freq/valid cascades that
-    # broke paramsd's angleOffset learner, calibrationd, and locationd's filter init.
-    # Keep the signals plumbed through frogpilotCarControl for when we re-enable.
+    # CLEARPILOT: variable framerate — 4/10fps when not engaged, 20fps when engaged
+    # (or lane changing / calibrating). Downstream services get a constant publish rate
+    # via the republish-caching below — only the GPU inference is skipped, so no
+    # freq_ok cascade in consumers.
     fpcc = sm['frogpilotCarControl']
-    lat_active = fpcc.latRequested  # noqa: F841
-    lane_changing = fpcc.noLatLaneChange  # noqa: F841
+    lat_active = fpcc.latRequested
+    lane_changing = fpcc.noLatLaneChange
     standstill = sm['carState'].standstill
-    calibrating = sm['liveCalibration'].calStatus != log.LiveCalibrationData.Status.calibrated  # noqa: F841
-    full_rate = True  # always 20fps when not standstill
+    calibrating = sm['liveCalibration'].calStatus != log.LiveCalibrationData.Status.calibrated
+    full_rate = lat_active or lane_changing or calibrating
 
-    # Standby transitions: standstill → 0fps (parked), otherwise → 20fps
-    should_standby = standstill
+    # Standby transitions (standstill only, when not at full rate)
+    should_standby = standstill and not full_rate
     if should_standby and not model_standby:
       params_memory.put_bool("ModelStandby", True)
       model_standby = True