feat(32-02): add mixer array comparison helper

- Add mixerArraysEqual helper to compare mixer arrays by ID
- Compares master.id + personal.id to create unique pair key
- Used to prevent unnecessary Redux dispatches when categorizing mixers

jam-ui/src/hooks/useMixerHelper.js

@@ -48,6 +48,29 @@ import { useGlobalContext } from '../context/GlobalContext.js';
 import { useVuContext } from '../context/VuContext.js';
 import { getAvatarUrl, getInstrumentIcon45, getInstrumentIcon24 } from '../helpers/utils.js';
 
+/**
+ * Compare two mixer arrays by their IDs to determine if content changed.
+ * Used to prevent unnecessary Redux dispatches when categorizing mixers.
+ *
+ * @param {Array} prev - Previous mixer array
+ * @param {Array} next - New mixer array
+ * @returns {boolean} True if arrays have same content (by ID)
+ */
+const mixerArraysEqual = (prev, next) => {
+  // Same reference = definitely equal
+  if (prev === next) return true;
+
+  // Different lengths = definitely not equal
+  if (!prev || !next || prev.length !== next.length) return false;
+
+  // Compare by mixer pair IDs (master.id + personal.id creates unique pair key)
+  const getIds = (arr) => arr
+    .map(pair => `${pair.master?.id || ''}-${pair.personal?.id || ''}`)
+    .sort()
+    .join(',');
+
+  return getIds(prev) === getIds(next);
+};
 
 const useMixerHelper = () => {
   const dispatch = useDispatch();