feat: add Session, Message, ToolCall models with migrations

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

tests/test_models.py

@@ -0,0 +1,57 @@
+from datetime import datetime, timezone
+
+import pytest
+from openclaw.models import Session, Message, ToolCall
+
+@pytest.mark.django_db
+class TestModelFields:
+    def test_session_creation(self):
+        s = Session.objects.create(
+            session_id="a" * 36,
+            agent_name="xingyao",
+            source_node="macmini",
+            status="active",
+        )
+        assert s.session_id == "a" * 36
+        assert s.total_tokens == 0
+        assert s.message_count == 0
+
+    def test_message_creation(self):
+        s = Session.objects.create(
+            session_id="b" * 36,
+            agent_name="test",
+            source_node="ubuntu1",
+            status="active",
+        )
+        msg = Message.objects.create(
+            session=s,
+            message_id="msg-001",
+            parent_id="root",
+            role="assistant",
+            timestamp=datetime(2026, 4, 5, 10, 0, tzinfo=timezone.utc),
+        )
+        assert msg.role == "assistant"
+        assert msg.tokens_total == 0
+
+    def test_toolcall_creation(self):
+        s = Session.objects.create(
+            session_id="c" * 36,
+            agent_name="test",
+            source_node="ubuntu2",
+            status="active",
+        )
+        msg = Message.objects.create(
+            session=s,
+            message_id="msg-002",
+            parent_id="root",
+            role="assistant",
+            timestamp=datetime(2026, 4, 5, 10, 0, tzinfo=timezone.utc),
+        )
+        tc = ToolCall.objects.create(
+            session=s,
+            message=msg,
+            tool_call_id="call_0",
+            tool_name="exec",
+        )
+        assert tc.tool_name == "exec"
+        assert tc.is_error is False