disable tlog calls, add param gate to tlog client

- Comment out all tlog() calls in controlsd (100Hz) and carstate (100Hz)
  — was causing controlsd to lag from JSON serialization + ZMQ overhead
- tlog() now checks TelemetryEnabled memory param (1/sec file read),
  returns immediately when disabled — zero cost when telemetry is off

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

selfdrive/clearpilot/telemetry.py

@@ -6,20 +6,39 @@ Usage from any process:
   tlog("canbus", {"speed": 45.2, "speed_limit": 60})
 
 Sends JSON packets over ZMQ PUSH to telemetryd, which diffs and writes CSV.
+Only sends when TelemetryEnabled memory param is set — zero cost when disabled.
 """
 import json
+import os
 import time
 import zmq
 
 TELEMETRY_SOCK = "ipc:///tmp/clearpilot_telemetry"
+_PARAM_PATH = "/dev/shm/params/d/TelemetryEnabled"
 
 _ctx = None
 _sock = None
+_last_check = 0
+_enabled = False
 
 
 def tlog(group: str, data: dict):
   """Log a telemetry packet. Only changed values will be written to CSV by telemetryd."""
-  global _ctx, _sock
+  global _ctx, _sock, _last_check, _enabled
+
+  # Check param at most once per second to avoid filesystem overhead
+  now = time.monotonic()
+  if now - _last_check > 1.0:
+    _last_check = now
+    try:
+      with open(_PARAM_PATH, 'r') as f:
+        _enabled = f.read().strip() == "1"
+    except (FileNotFoundError, IOError):
+      _enabled = False
+
+  if not _enabled:
+    return
+
   if _sock is None:
     _ctx = zmq.Context.instance()
     _sock = _ctx.socket(zmq.PUSH)