Add cumulative P&L banner to fund overview for at-a-glance profit/loss.

Expose period delta from equity curve start and surface it in the toolbar and summary cards with green/red cues.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_hub_fund_history_lib.py

@@ -5,6 +5,7 @@ from lib.hub.hub_fund_history_lib import (
     account_total_usdt,
     build_fund_overview,
     compute_drawdown,
+    compute_period_delta,
     get_fund_history,
     record_fund_snapshot,
 )
@@ -23,6 +24,20 @@ def test_compute_drawdown():
     assert dd["max_drawdown_pct"] == 25.0
 
 
+def test_compute_period_delta():
+    out = compute_period_delta(
+        [
+            {"day": "2026-06-09", "total_usdt": 100},
+            {"day": "2026-06-10", "total_usdt": 112.5},
+        ]
+    )
+    assert out["start_usdt"] == 100.0
+    assert out["period_delta_usdt"] == 12.5
+    assert out["period_delta_pct"] == 12.5
+    empty = compute_period_delta([])
+    assert empty["period_delta_usdt"] is None
+
+
 def test_build_fund_overview_skips_unmonitored(tmp_path, monkeypatch):
     hist_path = tmp_path / "hub_fund_history.json"
     monkeypatch.setattr("hub_fund_history_lib.FUND_HISTORY_PATH", hist_path)