Implement Kraken integration with REST and WebSocket clients, add market data handling, and enhance settings configuration

tests/unit/test_kraken_ws.py

@@ -0,0 +1,26 @@
+from arbitrade.config.settings import Settings
+from arbitrade.exchange.kraken_ws import KrakenWsClient
+
+
+def test_parse_book_delta() -> None:
+    client = KrakenWsClient(Settings())
+    message = {
+        "channel": "book",
+        "symbol": "BTC/USD",
+        "data": [
+            {
+                "bids": [{"price": "100.0", "qty": "1.2"}],
+                "asks": [{"price": "100.5", "qty": "0.8"}],
+                "checksum": 123,
+                "timestamp": 1717232000000,
+            }
+        ],
+    }
+
+    delta = client.parse_book_delta(message)
+
+    assert delta is not None
+    assert delta.symbol == "BTC/USD"
+    assert len(delta.bids) == 1
+    assert len(delta.asks) == 1
+    assert delta.checksum == 123