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

src/arbitrade/storage/repositories.py

@@ -0,0 +1,39 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from datetime import datetime
+from typing import Any
+
+import orjson
+
+from arbitrade.storage.db import DuckDBStore
+
+
+@dataclass(slots=True)
+class MarketSnapshotRecord:
+    snapshot_at: datetime
+    symbol: str
+    source: str
+    payload: dict[str, Any]
+    latency_ms: float | None
+
+
+class MarketSnapshotRepository:
+    def __init__(self, store: DuckDBStore) -> None:
+        self._store = store
+
+    def insert(self, record: MarketSnapshotRecord) -> None:
+        with self._store.connect() as conn:
+            conn.execute(
+                """
+                INSERT INTO market_snapshots (snapshot_at, symbol, source, payload, latency_ms)
+                VALUES (?, ?, ?, ?, ?)
+                """,
+                [
+                    record.snapshot_at,
+                    record.symbol,
+                    record.source,
+                    orjson.dumps(record.payload).decode("utf-8"),
+                    record.latency_ms,
+                ],
+            )