feat: Implement copytrading analytics and update WebUI

- Add v4 Tape-based CopytradingEstimator (Clustering, MAE, Tape Fills)
- Add CopytradingBacktestHarness (Walk-Forward testing, Shrinkage, LCB ranking)
- Add EF Core Migrations for FollowerFillPrice and Scoring fields
- Update WebUI: Fix Trader Detail tab layout blowout
- Update WebUI: Redesign Trader Detail menubar
- Update WebUI: Display separate Quality and Copyability metric cards
- Update WebUI: Add 'Highly Copyable' filter to Trader List

src/Predictalytics.Application/DTOs/TraderDto.cs

@@ -11,6 +11,8 @@ public record TraderDto(
     string Strategy,
     decimal CombinedScore,
     decimal CopytradingScore,
+    decimal CopytradingQualityScore,
+    decimal CopytradingCopyabilityScore,
     decimal WinRate,
     decimal TotalPnl,
     int TotalTrades,
@@ -38,6 +40,8 @@ public record TraderDetailDto(
     decimal TimingScore,
     decimal CombinedScore,
     decimal CopytradingScore,
+    decimal CopytradingQualityScore,
+    decimal CopytradingCopyabilityScore,
     int Rank,
     bool IsOnWatchlist,
     DateTime CreatedAt,