feat(api): Implement create conversation endpoint

tests/api/test_api_history.py

@@ -41,6 +41,27 @@ def test_get_conversations_success(auth_header, mock_user):
         assert len(response.json()) == 1
         assert response.json()[0]["name"] == "Conv 1"
 
+def test_create_conversation_success(auth_header, mock_user):
+    """Test creating a new conversation."""
+    with patch("ea_chatbot.api.routers.history.history_manager") as mock_hm:
+        mock_hm.create_conversation.return_value = Conversation(
+            id="c2",
+            name="New Conv",
+            user_id=mock_user.id,
+            data_state="nj",
+            created_at=datetime.now(timezone.utc)
+        )
+        
+        response = client.post(
+            "/conversations",
+            json={"name": "New Conv"},
+            headers=auth_header
+        )
+        
+        assert response.status_code == 201
+        assert response.json()["name"] == "New Conv"
+        assert response.json()["id"] == "c2"
+
 def test_get_messages_success(auth_header):
     """Test retrieving messages for a conversation."""
     with patch("ea_chatbot.api.routers.history.history_manager") as mock_hm: