feat(incident): config-driven TomTom min_magnitude filter

Add tomtom_incidents.min_magnitude setting (default 4 = severe)
to adapter_config registry. Replace the hardcoded magnitude==0
drop check with a config-driven floor that silently drops any
TomTom event below the configured threshold.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

meshai/adapter_config/defaults.py

@@ -180,6 +180,11 @@ REGISTRY: dict[tuple[str, str], dict[str, Any]] = {
         "type": "bool",
         "description": "Drop envelopes whose time_validity != 'present'.",
     },
+    ("tomtom_incidents", "min_magnitude"): {
+        "default": 4,
+        "type": "int",
+        "description": "Minimum TomTom magnitude_of_delay to broadcast (1=minor, 2=moderate, 3=major, 4=severe). Anything below this is silently dropped.",
+    },
 
     # =================================================================
     # STATE_511_ATIS -- 1 setting (states to skip in favor of itd_511)

meshai/central/incident_handler.py

@@ -272,10 +272,10 @@ def _parse_tomtom_incident(envelope: dict, now: int) -> Optional[dict]:
     inner = envelope.get("data") or {}
     d = inner.get("data") or {}
 
-    # FILTER §6: magnitude_of_delay == 0 -> drop at handler entrance.
-    # v0.6-3b: gated by adapter_config.tomtom_incidents.drop_zero_magnitude.
+    # Drop events below configured minimum magnitude.
     magnitude = d.get("magnitude_of_delay")
-    if magnitude == 0 and bool(adapter_config.tomtom_incidents.drop_zero_magnitude):
+    min_mag = int(adapter_config.tomtom_incidents.min_magnitude or 4)
+    if magnitude is not None and magnitude < min_mag:
         return None
 
     # FILTER §4: time_validity != 'present' -> drop past/future.