Add 'unknown' to public ObjectOperationAction for forward compatibility with unrecognized server values

The public type previously only allowed known operation actions
('map.set', 'map.create' etc), meaning any future operation action from
the server would be silently cast. Now the type explicitly includes
'unknown' so consumers can handle unrecognized values.

Author: VeskeR

liveobjects.d.ts

@@ -1931,6 +1931,10 @@ declare namespace ObjectOperationActions {
    * Object operation action for clearing a map object.
    */
   type MAP_CLEAR = 'map.clear';
+  /**
+   * Unrecognized object operation action received from the server.
+   */
+  type UNKNOWN = 'unknown';
 }
 
 /**
@@ -1943,7 +1947,8 @@ export type ObjectOperationAction =
   | ObjectOperationActions.COUNTER_CREATE
   | ObjectOperationActions.COUNTER_INC
   | ObjectOperationActions.OBJECT_DELETE
-  | ObjectOperationActions.MAP_CLEAR;
+  | ObjectOperationActions.MAP_CLEAR
+  | ObjectOperationActions.UNKNOWN;
 
 /**
  * The namespace containing the different types of map object semantics.

src/plugins/liveobjects/objectmessage.ts

@@ -27,6 +27,10 @@ const operationActions: ObjectsApi.ObjectOperationAction[] = [
   'map.clear',
 ];
 
+export function decodeObjectOperationAction(action: ObjectOperationAction): ObjectsApi.ObjectOperationAction {
+  return operationActions[action] || 'unknown';
+}
+
 /** @spec OMP2 */
 export enum ObjectsMapSemantics {
   LWW = 0,
@@ -617,7 +621,7 @@ function toUserFacingObjectOperation(operation: ObjectOperation<ObjectData>): Ob
   }
 
   return {
-    action: operationActions[operation.action] || 'unknown',
+    action: decodeObjectOperationAction(operation.action),
     objectId: operation.objectId,
     mapCreate,
     mapSet,