security: hard-disable all KIS trading paths (AEG-X-016)

Blocks submit, status, cancel, and settlement before HTTP or database writes and removes the KIS polling recurring job. Evidence: concrete adapter test 1/1 passed with zero HTTP calls. WBS remains IN_PROGRESS pending endpoint/startup override evidence.

src/KArtSell.Modules.ModelOperations/TradeExecution/KisTradeExecutionService.cs

@@ -25,6 +25,17 @@ public class KisTradeExecutionException : Exception
     }
 }
 
+public sealed class KisTradingDisabledException : InvalidOperationException
+{
+    public KisTradingDisabledException()
+        : base("KIS trading is hard-disabled. No buy, sell, cancel, status, or settlement call is permitted.") { }
+}
+
+public static class KisTradingHardOff
+{
+    public static void EnsureDisabled() => throw new KisTradingDisabledException();
+}
+
 public interface IKisTradeExecutionService
 {
     Task<(string OrderId, JsonElement Response)> ExecuteTradeAsync(Guid tradeId, int quantity, decimal limitPrice, Guid correlationId, CancellationToken ct = default);
@@ -56,6 +67,7 @@ public class KisTradeExecutionService : IKisTradeExecutionService
         Guid correlationId,
         CancellationToken ct = default)
     {
+        KisTradingHardOff.EnsureDisabled();
         var requestBody = new
         {
             symbol = "US0100",
@@ -120,6 +132,7 @@ public class KisTradeExecutionService : IKisTradeExecutionService
         Guid correlationId,
         CancellationToken ct = default)
     {
+        KisTradingHardOff.EnsureDisabled();
         var request = new HttpRequestMessage(HttpMethod.Get, $"{KisApiBase}/orders/{kisOrderId}");
         request.Headers.Add("X-Correlation-ID", correlationId.ToString());
 
@@ -159,6 +172,7 @@ public class KisTradeExecutionService : IKisTradeExecutionService
         Guid correlationId,
         CancellationToken ct = default)
     {
+        KisTradingHardOff.EnsureDisabled();
         var requestBody = new { reason = reason };
         var content = new StringContent(
             JsonSerializer.Serialize(requestBody),
@@ -195,6 +209,7 @@ public class KisTradeExecutionService : IKisTradeExecutionService
         Guid correlationId,
         CancellationToken ct = default)
     {
+        KisTradingHardOff.EnsureDisabled();
         var requestBody = new { confirm = true };
         var content = new StringContent(
             JsonSerializer.Serialize(requestBody),

src/KArtSell.Modules.ModelOperations/TradeExecution/TradeHandlers.cs

@@ -42,6 +42,7 @@ public class SubmitTradeHandler
 
     public async Task<Guid> HandleAsync(SubmitTradeCommand command, CancellationToken ct = default)
     {
+        KisTradingHardOff.EnsureDisabled();
         var trade = Trade.Create(command.SellDecisionId, command.Quantity, command.CorrelationId, _clock.UtcNow.UtcDateTime);
         await _sql.InsertTradeAsync(trade, ct);
         _logger.LogInformation("Created trade: {TradeId}", trade.Id);
@@ -127,6 +128,7 @@ public class PollTradeStatusHandler
 
     public async Task HandleAsync(PollTradeStatusCommand command, CancellationToken ct = default)
     {
+        KisTradingHardOff.EnsureDisabled();
         var trade = await _sql.GetTradeByIdAsync(command.TradeId, command.CorrelationId, ct);
         if (trade == null)
         {
@@ -222,6 +224,7 @@ public class ConfirmSettlementHandler
 
     public async Task HandleAsync(ConfirmSettlementCommand command, CancellationToken ct = default)
     {
+        KisTradingHardOff.EnsureDisabled();
         var trade = await _sql.GetTradeByIdAsync(command.TradeId, command.CorrelationId, ct);
         if (trade == null)
         {