refactor(29-01): wrap context consumers with React.memo

Components wrapped:
- SessionTrackGain: volume slider
- JKSessionMyTrack: local track display
- JKSessionVolumeModal: volume popup
- JKSessionPanModal: pan control popup
- JKSessionBackingTrack: backing track display
- JKSessionMetronome: metronome controls

Each component:
- Wrapped with memo(function ComponentName(...))
- Added displayName for debugging
- Preserved PropTypes

React.memo prevents re-renders when props haven't changed.
Combined with memoized context values, this eliminates
unnecessary re-renders across the component tree.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

jam-ui/src/components/client/JKSessionBackingTrack.js

@@ -1,4 +1,4 @@
-import React, { useState, useEffect } from 'react';
+import React, { useState, useEffect, memo } from 'react';
 import { useMixersContext } from '../../context/MixersContext';
 import { useJamClient } from '../../context/JamClientContext';
 import usePanHelpers from '../../hooks/usePanHelpers';
@@ -12,7 +12,7 @@ import { faTimes } from '@fortawesome/free-solid-svg-icons';
 import './JKSessionMyTrack.css';
 import backingTrackIcon from "../../icons/instruments/icon_instrument_default.svg"
 
-const JKSessionBackingTrack = ({
+const JKSessionBackingTrack = memo(function JKSessionBackingTrack({
   backingTrack,
   mixers,
   onClose
@@ -145,6 +145,8 @@ const JKSessionBackingTrack = ({
       )}
     </div>
   );
-};
+});
+
+JKSessionBackingTrack.displayName = 'JKSessionBackingTrack';
 
 export default JKSessionBackingTrack;

jam-ui/src/components/client/JKSessionMetronome.js

@@ -1,4 +1,4 @@
-import React from 'react';
+import React, { memo } from 'react';
 import { useMixersContext } from '../../context/MixersContext';
 import { useJamClient } from '../../context/JamClientContext';
 import SessionTrackVU from './SessionTrackVU';
@@ -6,7 +6,7 @@ import SessionTrackGain from './SessionTrackGain';
 import './JKSessionMyTrack.css';
 import computerIcon from '../../assets/img/instruments/icon_instrument_computer45_inverted.svg'
 
-const JKSessionMetronome = ({
+const JKSessionMetronome = memo(function JKSessionMetronome({
   mixers,
   onClose
 }) => {
@@ -112,6 +112,8 @@ const JKSessionMetronome = ({
       </div>
     </div>
   );
-};
+});
+
+JKSessionMetronome.displayName = 'JKSessionMetronome';
 
 export default JKSessionMetronome;

jam-ui/src/components/client/JKSessionMyTrack.js

@@ -1,4 +1,4 @@
-import React, { useState, useEffect } from 'react';
+import React, { useState, useEffect, memo } from 'react';
 import { useDispatch, useSelector } from 'react-redux';
 import { useMixersContext } from '../../context/MixersContext';
 import { useJamClient } from '../../context/JamClientContext';
@@ -20,7 +20,7 @@ import './JKSessionMyTrack.css';
 import pluginIcon from '../../assets/img/client/plugin.svg';
 import JKInstrumentIcon from '../profile/JKInstrumentIcon';
 
-const JKSessionMyTrack = ({
+const JKSessionMyTrack = memo(function JKSessionMyTrack({
   track,
   mixers,
   hasMixer,
@@ -341,6 +341,8 @@ const JKSessionMyTrack = ({
       )}
     </div>
   );
-};
+});
+
+JKSessionMyTrack.displayName = 'JKSessionMyTrack';
 
 export default JKSessionMyTrack;

jam-ui/src/components/client/JKSessionPanModal.js

@@ -1,4 +1,4 @@
-import React, { useState, useEffect } from 'react';
+import React, { useState, useEffect, memo } from 'react';
 import {
   Modal,
   ModalHeader,
@@ -11,7 +11,7 @@ import {
 import usePanHelpers from '../../hooks/usePanHelpers';
 import { useMixersContext } from '../../context/MixersContext';
 
-const JKSessionPanModal = ({ isOpen, toggle, mixers }) => {
+const JKSessionPanModal = memo(function JKSessionPanModal({ isOpen, toggle, mixers }) {
   const { convertPanToPercent, convertPercentToPan } = usePanHelpers();
   const mixerHelper = useMixersContext();
   const [panPercent, setPanPercent] = useState(50); // Center position
@@ -99,6 +99,8 @@ const JKSessionPanModal = ({ isOpen, toggle, mixers }) => {
       </ModalFooter>
     </Modal>
   );
-};
+});
+
+JKSessionPanModal.displayName = 'JKSessionPanModal';
 
 export default JKSessionPanModal;

jam-ui/src/components/client/JKSessionVolumeModal.js

@@ -1,4 +1,4 @@
-import React, { useEffect, useState, useCallback } from 'react';
+import React, { useEffect, useState, useCallback, memo } from 'react';
 import {
   Modal,
   ModalHeader,
@@ -10,7 +10,7 @@ import { useMixersContext } from '../../context/MixersContext';
 import { useJamClient } from '../../context/JamClientContext';
 import { MIX_MODES, ChannelGroupIds, CategoryGroupIds } from '../../helpers/globals.js';
 
-const JKSessionVolumeModal = ({ isOpen, toggle }) => {
+const JKSessionVolumeModal = memo(function JKSessionVolumeModal({ isOpen, toggle }) {
   const mixerHelper = useMixersContext();
   const jamClient = useJamClient();
   const mixers = mixerHelper.myTracks[0]?.mixers;
@@ -141,6 +141,8 @@ const JKSessionVolumeModal = ({ isOpen, toggle }) => {
       </ModalBody>
     </Modal>
   );
-};
+});
+
+JKSessionVolumeModal.displayName = 'JKSessionVolumeModal';
 
 export default JKSessionVolumeModal;

jam-ui/src/components/client/SessionTrackGain.js

@@ -1,10 +1,10 @@
-import React, { useState, useRef, useEffect, useLayoutEffect, useCallback } from 'react';
+import React, { useState, useRef, useEffect, useLayoutEffect, useCallback, memo } from 'react';
 import PropTypes from 'prop-types';
 import './VolumeSlider.css'; // Keep the same CSS for now
 import { useMixersContext } from '../../context/MixersContext';
 import useFaderHelpers from '../../hooks/useFaderHelpers';
 
-const SessionTrackGain = ({ mixers, gainType, controlGroup, sessionController, orientation = 'vertical' }) => {
+const SessionTrackGain = memo(function SessionTrackGain({ mixers, gainType, controlGroup, sessionController, orientation = 'vertical' }) {
 
   const mixerHelper = useMixersContext();
   const faderHelpers = useFaderHelpers();
@@ -177,7 +177,9 @@ const SessionTrackGain = ({ mixers, gainType, controlGroup, sessionController, o
       </div>
     </div>
   );
-};
+});
+
+SessionTrackGain.displayName = 'SessionTrackGain';
 
 SessionTrackGain.propTypes = {
   mixers: PropTypes.object,