chore: secure-trade closeout - strip [trade] gate probes, roadmap ledger

The two-client user gate PASSED 2026-08-14 (open both ways, stage with
the retail trading marker, accept/decline, executed swap, Clear All,
cancel text). Every TEMPORARY [trade] probe line from gate rounds 1-2 is
stripped (ItemInteractionController, SelectionInteractionController,
SecureTradeUiController, LiveSessionCommandRouter, WorldSession,
RuntimeTradeState). Roadmap gains the shipped-trade ledger row.

Suites after strip: App 4,992/3, Runtime 1,626 - green.

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

src/AcDream.Runtime/Gameplay/RuntimeTradeState.cs

@@ -98,10 +98,6 @@ public sealed class RuntimeTradeState : IDisposable
     /// </summary>
     public void ApplyRegister(GameEvents.RegisterTrade update, uint selfGuid)
     {
-        // TEMPORARY [trade] probe (2026-08-14 gate round 2).
-        Console.WriteLine(
-            $"[trade] register initiator=0x{update.Initiator:X8} "
-            + $"partner=0x{update.Partner:X8} self=0x{selfGuid:X8}");
         lock (_gate)
         {
             ObjectDisposedException.ThrowIf(_disposed, this);