feat(emulated-entrypoint): InProcessPairUp service for TK2 PvP matching

Tiny per-mode FCFS slot. First poller parks; second pairs and triggers
bridge.RegisterBattle(p1, p2, Pvp). Match cached for first poller's
next poll (consume-on-read). No MMR, no cross-mode, no timeouts --
the proper queue API is a separate spec; this is the smallest thing
that lets TK2 PvP work end-to-end.

SVSim.EmulatedEntrypoint/Program.cs

@@ -13,6 +13,7 @@ using SVSim.Database.Repositories.Viewer;
 using SVSim.Database.Services;
 using SVSim.EmulatedEntrypoint.Configuration;
 using SVSim.EmulatedEntrypoint.Extensions;
+using SVSim.EmulatedEntrypoint.Matching;
 using SVSim.EmulatedEntrypoint.Middlewares;
 using SVSim.EmulatedEntrypoint.Security.SteamSessionAuthentication;
 using SVSim.EmulatedEntrypoint.Services;
@@ -124,6 +125,10 @@ public class Program
             // BestHTTP's SocketManager parses this as the Socket.IO v2 endpoint URL.
             opt.NodeServerUrl = "localhost:5148/socket.io/";
         });
+        // In-process FCFS pair-up for TK2 PvP /do_matching. Singleton: per-mode state is
+        // process-wide. Proper queue API is a separate spec; this is enough to actually
+        // pair two viewers polling the same mode end-to-end.
+        builder.Services.AddSingleton<IMatchingPairUpService, InProcessPairUp>();
 
         builder.Services.AddTransient<ShadowverseTranslationMiddleware>();
         builder.Services.AddTransient<SessionidMappingMiddleware>();