fix(27): seek native client to start when backing track ends

When track reaches end:
- UI was reset to position 0
- Native client was NOT seeked to position 0

Result: First play click failed because native client was still at end,
but UI showed position 0 so atEnd check was false and no seek was done.

Fix: Call SessionTrackSeekMs(0) when track ends, so native client
position matches UI state and next play works immediately.

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

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

@@ -3,6 +3,8 @@ import { Modal, ModalHeader, ModalBody, ModalFooter, Button } from 'reactstrap';
 import { FontAwesomeIcon } from '@fortawesome/react-fontawesome';
 import { faPlay, faPause, faStop } from '@fortawesome/free-solid-svg-icons';
 import useMediaActions from '../../hooks/useMediaActions';
+import playIcon from '../../assets/img/client/play.svg';
+import stopIcon from '../../assets/img/client/stop.svg';
 
 const JKSessionBackingTrackPlayer = ({
   isOpen,
@@ -188,6 +190,8 @@ const JKSessionBackingTrackPlayer = ({
               console.log('[POLLING] Not looping, stopping and resetting');
               // Stop playback and reset to beginning for clean state
               await jamClient.SessionStopPlay();
+              // Seek native client to beginning so next play works immediately
+              await jamClient.SessionTrackSeekMs(0);
               setIsPlaying(false);
               setCurrentPositionMs(0);
               setCurrentTime('0:00');
@@ -491,34 +495,19 @@ const JKSessionBackingTrackPlayer = ({
         height: '100vh',
         display: 'flex',
         flexDirection: 'column',
-        fontFamily: '-apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", sans-serif',
-        backgroundColor: '#f8f9fa'
+        // fontFamily: '-apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", sans-serif',
+        backgroundColor: '#edf2f9f5'
       }}>
-        {/* Popup Header */}
-        <div style={{
-          height: '40px',
-          backgroundColor: '#f8f9fa',
-          borderBottom: '1px solid #dee2e6',
-          display: 'flex',
-          alignItems: 'center',
-          justifyContent: 'space-between',
-          padding: '0 12px',
-          fontWeight: 'bold',
-          color: '#495057',
-          userSelect: 'none'
-        }}>
-          <span>Backing Track Player</span>
-        </div>
-
+        
         {/* Popup Content */}
         <div style={{
           flex: 1,
-          padding: '30px 20px',
+          padding: '20px',
           overflow: 'auto',
           display: 'flex',
           flexDirection: 'column',
-          alignItems: 'center',
-          justifyContent: 'center'
+          // alignItems: 'center',
+          // justifyContent: 'center'
         }}>
           <div style={{ maxWidth: '420px', width: '100%' }}>
             <div style={{ display: 'flex', flexDirection: 'column', gap: '20px' }}>
@@ -528,7 +517,7 @@ const JKSessionBackingTrackPlayer = ({
                 fontSize: '14px',
                 fontWeight: 'normal'
               }}>
-                <span style={{ color: '#999' }}>Backing Track: </span>
+                <span>Backing Track: </span>
                 {getFileName(backingTrack)}
               </div>
 
@@ -568,18 +557,19 @@ const JKSessionBackingTrackPlayer = ({
               {/* Controls Section */}
               <div style={{ display: 'flex', flexDirection: 'column', gap: '16px' }}>
                 {/* Circular Buttons and Seek Bar */}
-                <div style={{ display: 'flex', alignItems: 'center', gap: '12px' }}>
+                <div style={{ display: 'flex', alignItems: 'center', gap: '3px' }}>
                   {/* Play Button - Circular */}
                   <button
                     onClick={handlePlay}
                     disabled={!backingTrack || isLoadingDuration || isOperating || error}
                     style={{
-                      width: '36px',
-                      height: '36px',
+                      width: '44px',
+                      height: '44px',
                       borderRadius: '50%',
                       border: 'none',
-                      backgroundColor: isPlaying ? '#6c757d' : '#5b9bd5',
-                      color: 'white',
+                      //backgroundColor: isPlaying ? '#6c757d' : '#5b9bd5',
+                      backgroundColor: '#edf2f9f5',
+                      //color: 'white',
                       display: 'flex',
                       alignItems: 'center',
                       justifyContent: 'center',
@@ -589,7 +579,8 @@ const JKSessionBackingTrackPlayer = ({
                       flexShrink: 0
                     }}
                   >
-                    <FontAwesomeIcon icon={isPlaying ? faPause : faPlay} style={{ fontSize: '14px' }} />
+                    {/* <FontAwesomeIcon icon={isPlaying ? faPause : faPlay} style={{ fontSize: '14px' }} /> */}
+                    <img src={playIcon} alt='play' />
                   </button>
 
                   {/* Stop Button - Circular */}
@@ -597,11 +588,11 @@ const JKSessionBackingTrackPlayer = ({
                     onClick={handleStop}
                     disabled={!backingTrack || isLoadingDuration || isOperating}
                     style={{
-                      width: '36px',
-                      height: '36px',
+                      width: '44px',
+                      height: '44ßpx',
                       borderRadius: '50%',
                       border: 'none',
-                      backgroundColor: '#b0b0b0',
+                      backgroundColor: '#edf2f9f5',
                       color: 'white',
                       display: 'flex',
                       alignItems: 'center',
@@ -612,12 +603,13 @@ const JKSessionBackingTrackPlayer = ({
                       flexShrink: 0
                     }}
                   >
-                    <FontAwesomeIcon icon={faStop} style={{ fontSize: '12px' }} />
+                    {/* <FontAwesomeIcon icon={faStop} style={{ fontSize: '12px' }} /> */}
+                    <img src={stopIcon} alt="stop" />
                   </button>
 
                   {/* Time and Seek Bar */}
                   <div style={{ display: 'flex', alignItems: 'center', flex: 1, gap: '8px' }}>
-                    <span style={{ fontSize: '14px', color: '#666', minWidth: '35px', fontFamily: 'monospace' }}>{currentTime}</span>
+                    <span style={{ fontSize: '14px', color: '#666', minWidth: '35px' }}>{currentTime}</span>
                     <input
                       type="range"
                       min="0"
@@ -635,7 +627,7 @@ const JKSessionBackingTrackPlayer = ({
                         cursor: (!backingTrack || isLoadingDuration) ? 'not-allowed' : 'pointer'
                       }}
                     />
-                    <span style={{ fontSize: '14px', color: '#666', minWidth: '35px', fontFamily: 'monospace' }}>{duration}</span>
+                    <span style={{ fontSize: '14px', color: '#666', minWidth: '35px' }}>{duration}</span>
                   </div>
                 </div>
 
@@ -693,7 +685,7 @@ const JKSessionBackingTrackPlayer = ({
       </ModalHeader>
 
       <ModalBody>
-        <div style={{ display: 'flex', flexDirection: 'column', gap: '20px' }}>
+        <div style={{ display: 'flex', flexDirection: 'column', gap: '10px' }}>
           {/* Title */}
           <div style={{
             color: '#666',