change ErrSessionIsTaken to EssSessionIsBusy

internal/server/gateway/route.go

@@ -26,8 +26,8 @@ func (gs *GatewayServer) Handle(w http.ResponseWriter, r *http.Request) {
 	if !gs.sm.Add(sessionUUID) {
 		rpc.WriteError(w, &rpc.RPCResponse{
 			Error: map[string]any{
-				"code":    rpc.ErrSessionIsTaken,
-				"message": rpc.ErrSessionIsTakenS,
+				"code":    rpc.ErrSessionIsBusy,
+				"message": rpc.ErrSessionIsBusyS,
 			},
 		})
 		return

internal/server/rpc/errors.go

@@ -25,6 +25,6 @@ const (
 	ErrMethodIsMissing  = -32020
 	ErrMethodIsMissingS = "Method is missing"
 
-	ErrSessionIsTaken  = -32030
-	ErrSessionIsTakenS = "The session is already taken"
+	ErrSessionIsBusy  = -32030
+	ErrSessionIsBusyS = "The session is busy"
 )