feat(deploy): optional dedicated-server travel via GAMESERVER_ADDRESS

When GAMESERVER_ADDRESS ("host:port") is set, EnterMatchmaking returns
that server (SingleplayerStation=false) and EnterMatchmakingMatch's
deploy signal carries its address, so the client travels to the real
game server instead of the client-hosted station. Unset = unchanged
(normal preprod). Lets a 2nd preprod run the same :preprod image and
differ only by this env var (dedicated-server test bench).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/Prospect.Server.Api/Services/CloudScript/Functions/EnterMatchmaking.cs

@@ -25,6 +25,24 @@ public class EnterMatchmakingFunction : ICloudScriptFunction<FYEnterMatchAzureFu
         //    SquadID = request.SquadId,
         //});
 
+        // Dedicated-server mode (2nd preprod): if GAMESERVER_ADDRESS ("host:port") is set, hand
+        // the client the real game server to travel to instead of the client-hosted station.
+        // Same image as preprod — only this env var flips the deployment type.
+        var gameServer = Environment.GetEnvironmentVariable("GAMESERVER_ADDRESS");
+        if (!string.IsNullOrEmpty(gameServer))
+        {
+            var parts = gameServer.Split(':');
+            return new FYEnterMatchAzureFunctionResult
+            {
+                Success = true,
+                ErrorMessage = "",
+                SingleplayerStation = false,
+                Address = parts[0],
+                Port = parts.Length > 1 && int.TryParse(parts[1], out var gsPort) ? gsPort : 7777,
+                MaintenanceMode = false,
+            };
+        }
+
         return new FYEnterMatchAzureFunctionResult
         {
             Success = true,