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_market_data_feed.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import asyncio
 from dataclasses import dataclass
 from datetime import UTC, datetime
 from types import SimpleNamespace
@@ -83,6 +84,31 @@ class _FakeFailingExecutor:
         raise RuntimeError("executor failure")
 
 
+class _FakeAlertNotifier:
+    def __init__(self) -> None:
+        self.events: list[dict[str, str]] = []
+
+    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 or {}),
+            }
+        )
+        return True
+
+
 @dataclass(slots=True)
 class _FakeWsClientTwoMessages:
     delta: BookDelta
@@ -430,3 +456,29 @@ async def test_market_data_feed_halts_on_repeated_execution_failures() -> None:
     assert stop_guard.halted_reason == "consecutive_failures_limit_breached"
     assert kill_switch.is_active
     assert kill_switch.reason == "consecutive_failures_limit_breached"
+
+
+@pytest.mark.asyncio
+async def test_market_data_feed_emits_critical_alert_on_executor_exception() -> None:
+    event = _sample_event(allocated_capital=75.0)
+    detector = _FakeDetector(event)
+    executor = _FakeFailingExecutor()
+    notifier = _FakeAlertNotifier()
+    feed = MarketDataFeed(
+        ws_client=_FakeWsClient(_sample_delta()),
+        snapshot_writer=_FakeSnapshotWriter(),
+        detector=detector,
+        opportunity_writer=_FakeOpportunityWriter(),
+        paper_trading_mode=False,
+        opportunity_executor=executor.execute,
+        alert_notifier=notifier,
+    )
+
+    await feed.run()
+    await asyncio.sleep(0)
+
+    assert executor.calls == 1
+    assert len(notifier.events) == 1
+    assert notifier.events[0]["category"] == "system"
+    assert notifier.events[0]["severity"] == "critical"
+    assert notifier.events[0]["title"] == "Critical execution exception"