fix(data): include the requested end date in yfinance fetches

yfinance treats end as exclusive, so get_YFin_data_online dropped the requested
end_date row and load_ohlcv dropped the current day. Request one day past the
end so the range is inclusive (look-ahead is still prevented by the curr_date
filter; the header still shows the requested range). Also correct the load_ohlcv
docstring to the 5-year window it actually downloads.

tests/test_date_boundaries.py

@@ -0,0 +1,61 @@
+"""yfinance treats ``end`` as exclusive; we must request one extra day so the
+requested end_date (and the current day) is actually included.
+
+Regressions for #986 (current-day OHLCV excluded) and #987 (requested end_date
+row omitted).
+"""
+import pandas as pd
+import pytest
+
+import tradingagents.dataflows.stockstats_utils as su
+import tradingagents.dataflows.y_finance as yfin
+from tradingagents.dataflows.config import set_config
+
+
+@pytest.mark.unit
+def test_get_yfin_requests_inclusive_end(monkeypatch):
+    captured = {}
+
+    class FakeTicker:
+        def __init__(self, symbol):
+            pass
+
+        def history(self, start, end):
+            captured["start"] = start
+            captured["end"] = end
+            idx = pd.to_datetime(["2025-05-08", "2025-05-09"])
+            return pd.DataFrame(
+                {"Open": [1.0, 2.0], "High": [1.0, 2.0], "Low": [1.0, 2.0],
+                 "Close": [1.0, 2.0], "Volume": [1, 2]},
+                index=idx,
+            )
+
+    monkeypatch.setattr(yfin.yf, "Ticker", FakeTicker)
+    out = yfin.get_YFin_data_online("AAPL", "2025-05-01", "2025-05-09")
+
+    # end is requested one day past end_date so 2025-05-09 is included (#987).
+    assert captured["end"] == "2025-05-10"
+    # Header still reflects the requested range, not the internal +1 day.
+    assert "to 2025-05-09" in out
+
+
+@pytest.mark.unit
+def test_load_ohlcv_requests_inclusive_end(monkeypatch, tmp_path):
+    set_config({"data_cache_dir": str(tmp_path)})
+    captured = {}
+
+    def fake_download(symbol, start, end, **kwargs):
+        captured["end"] = end
+        idx = pd.to_datetime([pd.Timestamp.today().normalize()])
+        return pd.DataFrame(
+            {"Open": [100.0], "High": [100.0], "Low": [100.0],
+             "Close": [100.0], "Volume": [1]},
+            index=idx,
+        )
+
+    monkeypatch.setattr(su.yf, "download", fake_download)
+    today = pd.Timestamp.today().strftime("%Y-%m-%d")
+    su.load_ohlcv("AAPL", today)
+
+    expected_end = (pd.Timestamp.today() + pd.Timedelta(days=1)).strftime("%Y-%m-%d")
+    assert captured["end"] == expected_end  # tomorrow -> today's row included (#986)