Add trade setup outcome tracking and performance stats

Closes the feedback loop on R:R scanner signals:

- Nightly outcome_evaluator job replays unresolved setups against daily
  OHLCV bars: target_hit / stop_hit / ambiguous (same-bar, counted as
  loss) / expired after OUTCOME_EVALUATION_MAX_BARS (default 30)
- Migration 004: evaluated_at + outcome_date on trade_setups
- GET /trades/performance: hit rate, expectancy (avg R), total R with
  breakdowns by direction, recommended action, and confidence bucket
- New Performance page (stat cards, breakdown tables, Evaluate Now,
  methodology disclosure) wired into sidebar and mobile nav
- 17 new unit tests for evaluation logic and stats aggregation

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

app/services/rr_scanner_service.py

@@ -351,4 +351,6 @@ def _trade_setup_to_dict(setup: TradeSetup, symbol: str) -> dict:
         "reasoning": setup.reasoning,
         "risk_level": setup.risk_level,
         "actual_outcome": setup.actual_outcome,
+        "outcome_date": setup.outcome_date,
+        "evaluated_at": setup.evaluated_at,
     }