feat: add audit events and runtime state snapshots to database

- Introduced new tables for audit events and runtime state snapshots in the database schema.
- Created data classes for AuditRecord and RuntimeStateRecord to represent the new entities.
- Implemented AuditRepository and RuntimeStateRepository for inserting and retrieving records.
- Enhanced the dashboard to include an audit trail section, displaying recent audit events.
- Added tests for the new audit repository and runtime lifecycle functionalities.
- Updated settings validation to ensure proper configuration for alerting features.
- Integrated alert notifications across various components, including execution sequencer and loss limits.

tests/unit/test_trade_limits.py

@@ -1,10 +1,38 @@
 from __future__ import annotations
 
+import asyncio
+from typing import Any
+
 import pytest
 
 from arbitrade.risk.trade_limits import TradeLimitsGuard
 
 
+class _FakeAlertNotifier:
+    def __init__(self) -> None:
+        self.events: list[dict[str, Any]] = []
+
+    async def notify(
+        self,
+        *,
+        category: str,
+        severity: str,
+        title: str,
+        message: str,
+        details: dict[str, str] | None = None,
+    ) -> bool:
+        self.events.append(
+            {
+                "category": category,
+                "severity": severity,
+                "title": title,
+                "message": message,
+                "details": details or {},
+            }
+        )
+        return True
+
+
 def test_trade_limits_guard_blocks_when_max_concurrent_reached() -> None:
     guard = TradeLimitsGuard(max_concurrent_trades=1)
 
@@ -39,3 +67,18 @@ def test_trade_limits_guard_rejects_invalid_configuration() -> None:
 
     with pytest.raises(ValueError, match="max_exposure_per_asset"):
         TradeLimitsGuard(max_exposure_per_asset=0.0)
+
+
+@pytest.mark.asyncio
+async def test_trade_limits_guard_emits_alert_when_rejecting_trade() -> None:
+    notifier = _FakeAlertNotifier()
+    guard = TradeLimitsGuard(max_concurrent_trades=1, alert_notifier=notifier)
+
+    guard.open_trade({"BTC": 10.0})
+    allowed = guard.is_trade_allowed({"BTC": 1.0})
+    await asyncio.sleep(0)
+
+    assert not allowed
+    assert len(notifier.events) == 1
+    assert notifier.events[0]["category"] == "threshold"
+    assert notifier.events[0]["title"] == "Concurrent trade limit reached"