fix: correct hedge equity math at downside scenarios

tests/test_e2e_playwright.py

@@ -96,6 +96,17 @@ def test_homepage_and_options_page_render() -> None:
         assert "Scenario Summary" in hedge_text
         assert "RuntimeError" not in hedge_text
         assert "Server error" not in hedge_text
+
+        slider = page.locator(".q-slider").first
+        slider_box = slider.bounding_box()
+        assert slider_box is not None
+        page.mouse.click(slider_box["x"] + slider_box["width"] * 0.1, slider_box["y"] + slider_box["height"] / 2)
+        expect(page.locator("text=Scenario move: -20%").first).to_be_visible(timeout=15000)
+        hedge_text = page.locator("body").inner_text(timeout=15000)
+        assert "Unhedged equity" in hedge_text
+        assert "Hedged equity" in hedge_text
+        assert "$27,000" in hedge_text
+        assert "$58,750" in hedge_text
         page.screenshot(path=str(ARTIFACTS / "hedge.png"), full_page=True)
 
         browser.close()