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_audit_repository.py

@@ -0,0 +1,34 @@
+from __future__ import annotations
+
+from datetime import UTC, datetime
+
+from arbitrade.config.settings import Settings
+from arbitrade.storage.db import DuckDBStore
+from arbitrade.storage.repositories import AuditRecord, AuditRepository
+
+
+def test_audit_repository_inserts_and_lists_recent(tmp_path) -> None:
+    settings = Settings(_env_file=None, DUCKDB_PATH=tmp_path / "audit.duckdb")
+    store = DuckDBStore(settings)
+    store.migrate()
+    repository = AuditRepository(store)
+
+    repository.insert(
+        AuditRecord(
+            occurred_at=datetime.now(UTC),
+            actor="dashboard_user",
+            event_type="dashboard.control.start",
+            decision="approved",
+            payload={"execution_status": "running"},
+            correlation_id="req-1",
+        )
+    )
+
+    recent = repository.list_recent(limit=5)
+
+    assert len(recent) == 1
+    assert recent[0].actor == "dashboard_user"
+    assert recent[0].event_type == "dashboard.control.start"
+    assert recent[0].decision == "approved"
+    assert recent[0].payload == {"execution_status": "running"}
+    assert recent[0].correlation_id == "req-1"