operator-plane: wire research reader into standalone dashboard (sparklines)

DashboardState.bars() short-circuits to [] unless a research_con is attached; the
embedded orchestrator passed one but the standalone dashboard_api.py never built
it, so production sparklines were permanently dead. The missing wire was purely
the entrypoint (DATABASE_URL already reaches the market schema) — now it opens
open_research_db("market") read-only and passes it, degrading to None (charts
show "no research db") if it can't connect. Verified live: bars() returns real
minute rows through the standalone reader.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/unit/api/test_dashboard_sparklines.py

@@ -0,0 +1,38 @@
+"""Standalone dashboard sparklines: the fix is a NON-None research reader
+(plan 007 step 5). Without it bars() short-circuits; with one it runs the query
+(an empty array on a bare DB is still a PASS)."""
+
+import pandas as pd
+
+from api.main import DashboardState
+
+
+class _FakeResult:
+    def df(self):
+        return pd.DataFrame()
+
+    def fetchone(self):
+        return [None]
+
+
+class _FakeResearchCon:
+    def execute(self, *args, **kwargs):
+        return _FakeResult()
+
+
+def test_bars_without_reader_reports_missing_db():
+    out = DashboardState("momentum", research_con=None).bars("AAPL")
+    assert out["bars"] == []
+    assert out.get("reason") == "no research db attached"
+
+
+def test_bars_with_reader_runs_query():
+    out = DashboardState("momentum", research_con=_FakeResearchCon()).bars("AAPL")
+    # the reader path ran (empty DB -> empty array, but NOT the "no db" short-circuit)
+    assert out["bars"] == []
+    assert "reason" not in out
+
+
+if __name__ == "__main__":  # pragma: no cover
+    import pytest
+    pytest.main([__file__, "-q"])