fix(export): MIDI project WAV export qua server offline render thay vi bounce realtime

Bounce REALTIME race (note-on drop sau STOP / channel reload / watchdog
recovery) ra file chi 1 note roi cam hoac cam han. Offline render server
deterministic da xac nhan ra nhac day du (42.67s RMS ~0.24 moi giay).

triggerWavExport: project co MIDI + source=project + format=wav -> goi
renderMasteringExport (server /api/v1/plugins/render) thay vi bounce.
Bounce chi la fallback khi server disconnected va cache MIDI khong du.

app/templates/index.html

@@ -51,7 +51,7 @@
     <script src="/static/js/services/promptTemplateManager.js?v=202607281039"></script>
     <script src="/static/js/services/undoRedoEngine.js?v=202607290941"></script>
     <script src="/static/js/services/chordTheory.js?v=202608211300"></script>
-    <script src="/static/js/app.precompiled.js?v=202608250101" defer></script>
+    <script src="/static/js/app.precompiled.js?v=202608250102" defer></script>
     <link rel="stylesheet" href="/static/css/styles.css?v=202607271016">
     <style>
         :root {