Add missing setup_transfer_caches() to bssnEM_class::Initialize()

bssnEScalar_class::Initialize() already calls setup_transfer_caches(),
but bssnEM_class::Initialize() did not. When USE_TRANSFER_CACHE=1,
the sync_cache pointers remain NULL, causing SIGSEGV in wrapper
methods that dereference sync_cache_*[lev].

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

AMSS_NCKU_source/bssnEM_class.C

@@ -258,6 +258,8 @@ void bssnEM_class::Initialize()
     PhysTime = StartTime;
     Setup_Black_Hole_position();
   }
+
+  setup_transfer_caches();
 }
 
 //================================================================================================