add earnings-date guard — warn when a report falls in the target horizon

Finnhub's earnings calendar now supplies next_earnings_date through the
fundamentals chain; persisted on fundamental_data (migration 006) and exposed in
the fundamentals API. The recommendation panel warns when earnings fall within
the ~30-day target horizon (a report can gap price through stop/target) and
otherwise shows the next date. Informational only.

Deploy: run alembic upgrade (new fundamental_data.next_earnings_date column).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/scheduler.py

@@ -599,6 +599,7 @@ async def collect_fundamentals() -> None:
                     revenue_growth=data.revenue_growth,
                     earnings_surprise=data.earnings_surprise,
                     market_cap=data.market_cap,
+                    next_earnings_date=data.next_earnings_date,
                     unavailable_fields=data.unavailable_fields,
                 )