feature/IO-3000-messaging-sockets-migrations2 -

- A lot of a lot of testing....

Signed-off-by: Dave Richer <dave@imexsystems.ca>

client/src/utils/GraphQLClient.js

@@ -162,6 +162,22 @@ const cache = new InMemoryCache({
                 (incomingItem) => !existing.some((existingItem) => existingItem.__ref === incomingItem.__ref)
               )
             ];
+            return merged;
+          }
+        },
+        messages: {
+          keyArgs: false, // Ignore arguments when determining uniqueness (like `order_by`).
+          merge(existing = [], incoming = [], { readField }) {
+            const existingIds = new Set(existing.map((message) => readField("id", message)));
+
+            // Merge incoming messages, avoiding duplicates
+            const merged = [...existing];
+            incoming.forEach((message) => {
+              if (!existingIds.has(readField("id", message))) {
+                merged.push(message);
+              }
+            });
+
             return merged;
           }
         }