feat(PORT-003): add historical ltv charts

tests/test_overview_ltv_history_playwright.py

@@ -0,0 +1,57 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+from playwright.sync_api import expect, sync_playwright
+
+BASE_URL = "http://127.0.0.1:8000"
+ARTIFACTS = Path("tests/artifacts")
+ARTIFACTS.mkdir(parents=True, exist_ok=True)
+
+
+def test_overview_shows_ltv_history_and_exports_csv() -> None:
+    with sync_playwright() as p:
+        browser = p.chromium.launch(headless=True)
+        page = browser.new_page(viewport={"width": 1440, "height": 1000})
+
+        page.goto(BASE_URL, wait_until="domcontentloaded", timeout=30000)
+        expect(page.locator("text=Create a private workspace URL").first).to_be_visible(timeout=15000)
+        page.get_by_role("button", name="Get started").click()
+        page.wait_for_url(f"{BASE_URL}/*", timeout=15000)
+
+        expect(page.locator("text=Overview").first).to_be_visible(timeout=15000)
+        expect(page.locator("text=Historical LTV").first).to_be_visible(timeout=15000)
+        expect(page.locator("text=7 Day").first).to_be_visible(timeout=15000)
+        expect(page.locator("text=30 Day").first).to_be_visible(timeout=15000)
+        expect(page.locator("text=90 Day").first).to_be_visible(timeout=15000)
+        expect(page.get_by_role("button", name="Export CSV")).to_be_visible(timeout=15000)
+
+        series_names = page.evaluate("""
+            async () => {
+              const importMap = JSON.parse(document.querySelector('script[type="importmap"]').textContent).imports;
+              const mod = await import(importMap['nicegui-echart']);
+              const chart = mod.echarts.getInstanceByDom(document.querySelector('.nicegui-echart'));
+              return chart ? chart.getOption().series.map(series => series.name) : [];
+            }
+            """)
+        assert series_names == ["LTV", "Margin threshold"]
+
+        with page.expect_download() as download_info:
+            page.get_by_role("button", name="Export CSV").click()
+        download = download_info.value
+        assert download.suggested_filename.endswith("-ltv-history.csv")
+        download_path = ARTIFACTS / "ltv-history-export.csv"
+        download.save_as(str(download_path))
+        csv_content = download_path.read_text()
+        assert (
+            "snapshot_date,captured_at,ltv_ratio_pct,margin_threshold_pct,loan_amount_usd,collateral_value_usd,spot_price_usd_per_ozt,source"
+            in csv_content
+        )
+
+        body = page.locator("body").inner_text(timeout=15000)
+        assert "RuntimeError" not in body
+        assert "Server error" not in body
+        assert "Traceback" not in body
+        page.screenshot(path=str(ARTIFACTS / "overview-ltv-history.png"), full_page=True)
+
+        browser.close()