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>

frontend/src/lib/types.ts

@@ -128,9 +128,30 @@ export interface TradeSetup {
   reasoning: string | null;
   risk_level: 'Low' | 'Medium' | 'High' | null;
   actual_outcome: string | null;
+  outcome_date: string | null;
+  evaluated_at: string | null;
   recommendation_summary?: RecommendationSummary;
 }
 
+// Performance / outcome statistics
+export interface OutcomeBucketStats {
+  total: number;
+  wins: number;
+  losses: number;
+  expired: number;
+  hit_rate: number | null;
+  avg_r: number | null;
+  total_r: number | null;
+}
+
+export interface PerformanceStats {
+  overall: OutcomeBucketStats;
+  pending: number;
+  by_direction: Record<string, OutcomeBucketStats>;
+  by_action: Record<string, OutcomeBucketStats>;
+  by_confidence: Record<string, OutcomeBucketStats>;
+}
+
 export interface TradeTarget {
   price: number;
   distance_from_entry: number;