Fix API offset limit 400 Bad Request, implement requested UI/UX improvements

src/Predictalytics.Domain/Entities/Market.cs

@@ -14,7 +14,7 @@ public class Market
 
     /// <summary>The Event this market belongs to.</summary>
     public int EventId { get; set; }
-    public virtual Event Event { get; set; }
+    public virtual Event Event { get; set; } = null!;
 
     /// <summary>Platform-specific numeric market identifier.</summary>
     public long PlatformMarketId { get; set; }
@@ -57,12 +57,16 @@ public class Market
 
     /// <summary>When the market closes / resolves.</summary>
     public DateTime? EndDate { get; set; }
+    public DateTime? ClosedAt { get; set; }
 
     /// <summary>Whether the market has been resolved.</summary>
     public bool IsResolved { get; set; }
 
     /// <summary>Resolution outcome (if resolved).</summary>
     public string? ResolutionOutcome { get; set; }
+    
+    public decimal FeeRateBps { get; set; }
+    public bool IsNegRisk { get; set; }
 
     /// <summary>When this market was created on the platform.</summary>
     public DateTime CreatedAt { get; set; }