feat(multiplayer): add degraded admission mode

server/api/service.go

@@ -127,6 +127,7 @@ type Service struct {
 	RankedProfileProvider RankedProfileProvider
 	TierPolicy            domain.TierPolicy
 	RateLimiter           *RateLimiter
+	Admission             AdmissionController
 	// Log receives a credential-safe structured event for lifecycle-relevant
 	// reads and mutations. Nil
 	// is a valid, silent no-op -- every call site must stay optional so
@@ -213,6 +214,16 @@ func (s *Service) Handler() http.Handler {
 			mux.ServeHTTP(w, r)
 		})
 	}
+	if s.Admission != nil {
+		admissionHandler := handler
+		handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			if operation := admissionOperation(r.URL.Path, r.Method); operation != "" && !s.Admission.Allow(operation) {
+				writeError(w, http.StatusServiceUnavailable, "service_degraded")
+				return
+			}
+			admissionHandler.ServeHTTP(w, r)
+		})
+	}
 	if s.Metrics == nil {
 		return handler
 	}