perf: reuse browser across chart scrapes

tests/test_scraper_semantics.py

@@ -1,3 +1,5 @@
+from contextlib import contextmanager
+
 from scrapers import lookintobitcoin
 from scoring import engine
 
@@ -26,3 +28,29 @@ def test_vdd_derived_return_is_labeled_as_momentum_not_raw_multiple():
 
     assert vdd["name"] == "VDD 30-Period Momentum"
     assert vdd["transform"] == "30_period_return"
+
+
+def test_scrape_all_reuses_one_browser_page(monkeypatch):
+    page = object()
+    seen_pages = []
+
+    @contextmanager
+    def fake_browser_page():
+        yield page
+
+    def fake_scrape_chart(_path, timeout=25000, page=None):
+        seen_pages.append(page)
+        return [{"name": "metric", "y": [1.0]}]
+
+    monkeypatch.setattr(lookintobitcoin, "CHARTS", {
+        "first": {"path": "/first", "traces": ["metric"]},
+        "second": {"path": "/second", "traces": ["metric"]},
+    })
+    monkeypatch.setattr(lookintobitcoin, "browser_page", fake_browser_page)
+    monkeypatch.setattr(lookintobitcoin, "scrape_chart", fake_scrape_chart)
+
+    result = lookintobitcoin.scrape_all()
+
+    assert seen_pages == [page, page]
+    assert result["first"]["value"] == 1.0
+    assert result["second"]["value"] == 1.0