fix(CORE-001D3A): accept decimal boundary inputs

tests/test_alerts.py

@@ -14,14 +14,14 @@ def alert_service(tmp_path: Path) -> AlertService:
     return AlertService(history_path=tmp_path / "alert_history.json")
 
 
-def test_normalize_alert_evaluation_input_coerces_numeric_boundary_values() -> None:
+def test_normalize_alert_evaluation_input_accepts_decimal_boundary_values() -> None:
     config = PortfolioConfig(gold_value=215_000.0, entry_price=215.0, loan_amount=151_000.0)
 
     normalized = _normalize_alert_evaluation_input(
         config,
         {
-            "ltv_ratio": "0.7023",
-            "spot_price": "215.0",
+            "ltv_ratio": Decimal("0.7023"),
+            "spot_price": Decimal("215.0"),
             "quote_updated_at": 123,
         },
     )
@@ -33,6 +33,38 @@ def test_normalize_alert_evaluation_input_coerces_numeric_boundary_values() -> N
     assert normalized.critical_threshold == Decimal("0.75")
 
 
+def test_alert_service_evaluate_accepts_string_boundary_values(alert_service: AlertService) -> None:
+    config = PortfolioConfig(gold_value=215_000.0, entry_price=215.0, loan_amount=151_000.0)
+
+    status = alert_service.evaluate(
+        config,
+        {
+            "ltv_ratio": "0.7023",
+            "spot_price": "215.0",
+            "quote_updated_at": "2026-03-24T12:00:00Z",
+        },
+        persist=False,
+    )
+
+    assert status.severity == "warning"
+    assert status.ltv_ratio == pytest.approx(0.7023, rel=1e-9)
+    assert [event.severity for event in status.history] == ["warning"]
+
+
+def test_alert_service_rejects_missing_ltv_ratio(alert_service: AlertService) -> None:
+    config = PortfolioConfig(gold_value=215_000.0, entry_price=215.0, loan_amount=151_000.0)
+
+    with pytest.raises(ValueError, match="portfolio.ltv_ratio must be present"):
+        alert_service.evaluate(
+            config,
+            {
+                "spot_price": 215.0,
+                "quote_updated_at": "2026-03-24T12:00:00Z",
+            },
+            persist=False,
+        )
+
+
 def test_normalize_alert_evaluation_input_rejects_bool_values() -> None:
     config = PortfolioConfig(gold_value=215_000.0, entry_price=215.0, loan_amount=151_000.0)