game-server: catch-all request capture for squad-invite RE

Log every unrouted POST at Warning [CAPTURE UNROUTED] (reveals native PlayFab
endpoints the emulator doesn't implement, e.g. /Group/CreateGroup, /Lobby/*) and
every social/squad/invite/friend/matchmaking call (path or body) at Information
[CAPTURE SOCIAL]. Lets us pin the exact invite mechanism when reproduced in game.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/Prospect.Server.Api/Middleware/RequestLoggerMiddleware.cs

@@ -9,6 +9,14 @@ public class RequestLoggerMiddleware
     private readonly ILogger<RequestLoggerMiddleware> _logger;
     private readonly RequestDelegate _next;
 
+    // Keywords used to surface social/squad/invite traffic while reverse-engineering the
+    // squad-invite flow (see SQUAD-EMULATION.md). Matched against the path AND the body
+    // (the CloudScript function name lives in the body of /Client/ExecuteFunction).
+    private static readonly string[] SocialKeywords =
+    {
+        "group", "party", "lobby", "squad", "invite", "friend", "social", "matchmak",
+    };
+
     public RequestLoggerMiddleware(ILogger<RequestLoggerMiddleware> logger, RequestDelegate next)
     {
         _logger = logger;
@@ -32,6 +40,27 @@ public class RequestLoggerMiddleware
         }
 
         await _next(context);
+
+        // ── Capture pass (squad-invite RE, see SQUAD-EMULATION.md) ──────────────
+        // Runs AFTER the pipeline so we know whether the request was actually routed.
+        if (context.Request.Method == "POST")
+        {
+            var path = context.Request.Path.Value ?? "";
+            var haystack = (path + " " + body).ToLowerInvariant();
+
+            // Any POST that fell through to a 404 = an endpoint the emulator does NOT implement
+            // (e.g. a native PlayFab /Group/CreateGroup or /Lobby/* the client tried to call).
+            if (context.Response.StatusCode == 404)
+            {
+                _logger.LogWarning("[CAPTURE UNROUTED] {Method} {Url} -> 404 | Body {Body}",
+                    context.Request.Method, context.Request.GetDisplayUrl(), body);
+            }
+            else if (SocialKeywords.Any(k => haystack.Contains(k)))
+            {
+                _logger.LogInformation("[CAPTURE SOCIAL] {Url} ({Status}) | Body {Body}",
+                    context.Request.GetDisplayUrl(), context.Response.StatusCode, body);
+            }
+        }
     }
 
     private static async Task<string> RequestAsync(HttpRequest request)