modeld 3-mode power saving, tlog disabled, dashcamd boot fix

- modeld: full 20fps (lat active), 4fps (driving no lateral), 0fps
  (standstill). Standby timestamp written in both standby and 4fps modes
  to suppress transient errors on engagement transition
- tlog: all calls commented out (was causing 100Hz CPU load in controlsd
  and carstate). tlog client now checks TelemetryEnabled param before
  sending — zero cost when disabled
- dashcamd: wait for valid frame dimensions on startup (fix SIGSEGV),
  always_run (manages own trip lifecycle)
- Fan: driving range 15-100%

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

selfdrive/modeld/modeld.py

@@ -241,16 +241,21 @@ def main(demo=False):
 
     sm.update(0)
 
-    # CLEARPILOT: power saving — skip inference when lateral control is not active
-    # Covers standstill, manual driving (no cruise), and disengaged states
-    # Exception: keep processing during lane changes (no_lat_lane_change)
+    # CLEARPILOT: power saving — three modes based on driving state
+    #   Full 20fps: lat active or lane changing
+    #   Reduced 4fps: not lat active, not standstill (driving without cruise)
+    #   Standby 0fps: standstill
     lat_active = sm['carControl'].latActive
     lane_changing = params_memory.get_bool("no_lat_lane_change")
-    should_standby = not lat_active and not lane_changing
+    standstill = sm['carState'].standstill
+    full_rate = lat_active or lane_changing
+
+    # Standby transitions (standstill only)
+    should_standby = standstill and not full_rate
     if should_standby and not model_standby:
       params_memory.put_bool("ModelStandby", True)
       model_standby = True
-      cloudlog.warning("modeld: standby ON (lat_active=%s standstill=%s)", lat_active, sm['carState'].standstill)
+      cloudlog.warning("modeld: standby ON (standstill)")
     elif not should_standby and model_standby:
       params_memory.put_bool("ModelStandby", False)
       model_standby = False
@@ -265,6 +270,19 @@ def main(demo=False):
       last_vipc_frame_id = meta_main.frame_id
       continue
 
+    # Reduced framerate: 4fps when not lat active and not standstill
+    # Skip 4 out of every 5 frames (20fps -> 4fps)
+    # Write standby timestamp so controlsd suppresses transient errors
+    if not full_rate:
+      now = _time.monotonic()
+      if now - last_standby_ts_write > 1.0:
+        params_memory.put("ModelStandbyTs", str(now))
+        last_standby_ts_write = now
+      if run_count % 5 != 0:
+        last_vipc_frame_id = meta_main.frame_id
+        run_count += 1
+        continue
+
     desire = DH.desire
     is_rhd = sm["driverMonitoringState"].isRHD
     frame_id = sm["roadCameraState"].frameId