BEHAVIOR-003: learn causal shadow triggers

app/ha/reader.py

@@ -53,6 +53,7 @@ class HaReader:
                     entity_id=entity_id,
                     domain=domain,
                     state=_optional_str(item.get("state")),
+                    last_changed=_optional_datetime(item.get("last_changed")),
                     state_class=_optional_str(attributes.get("state_class")),
                     device_class=_optional_str(attributes.get("device_class")),
                     unit_of_measurement=_optional_str(attributes.get("unit_of_measurement")),
@@ -116,3 +117,13 @@ def _optional_str(value: object) -> str | None:
     if value is None or value == "":
         return None
     return str(value)
+
+
+def _optional_datetime(value: object) -> datetime | None:
+    if not isinstance(value, str) or not value:
+        return None
+    try:
+        parsed = datetime.fromisoformat(value.replace("Z", "+00:00"))
+    except ValueError:
+        return None
+    return parsed if parsed.tzinfo is not None else None