feat(PRICING-001): add GLD expense ratio decay correction

tests/test_hedge_metrics.py

@@ -62,7 +62,11 @@ def test_cost_benefit_chart_shows_positive_downside_benefit_when_puts_are_in_the
 
 
 def test_hedge_quote_resolution_converts_gld_share_price_to_ozt_spot() -> None:
-    """Hedge page should convert GLD share quotes to USD/ozt for display."""
+    """Hedge page should convert GLD share quotes to USD/ozt using expense-adjusted backing."""
+    from datetime import date
+
+    from app.domain.instruments import gld_ounces_per_share
+
     config = PortfolioConfig(entry_price=4400.0, gold_ounces=220.0, entry_basis_mode="weight", loan_amount=145000.0)
     share_quote = {
         "symbol": "GLD",
@@ -74,7 +78,10 @@ def test_hedge_quote_resolution_converts_gld_share_price_to_ozt_spot() -> None:
 
     spot, source, updated_at = resolve_portfolio_spot_from_quote(config, share_quote)
 
-    assert spot == 4041.9
+    # With expense-adjusted backing (~0.0916 oz/share), spot = 404.19 / 0.091576... ≈ 4413.71
+    current_backing = float(gld_ounces_per_share(date.today()))
+    expected_spot = 404.19 / current_backing
+    assert abs(spot - expected_spot) < 0.01
     assert source == "yfinance"