feat(mq_editor): add new partial, undo/redo

- '+ Partial' button (N key): insert 440Hz/max-amp partial at front
- Undo/Redo buttons (Ctrl+Z/Y): JSON snapshot stack, 50 levels
- Hooks in delete, mute, curve edits, amp drag, freq drag

handoff(Gemini): undo/redo + new-partial added to mq_editor

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 80 insertions, 0 deletions

diff --git a/tools/mq_editor/app.js b/tools/mq_editor/app.js
index 90f8f7e..862ec6c 100644
--- a/tools/mq_editor/app.js
+++ b/tools/mq_editor/app.js
@@ -46,6 +46,45 @@ let currentSource = null;
 let extractedPartials = null;
 let stftCache = null;
 
+// Undo/redo
+const undoStack = [];
+const redoStack = [];
+
+function _updateUndoRedoBtns() {
+  document.getElementById('undoBtn').disabled = undoStack.length === 0;
+  document.getElementById('redoBtn').disabled = redoStack.length === 0;
+}
+
+function pushUndo() {
+  undoStack.push(JSON.parse(JSON.stringify(extractedPartials || [])));
+  redoStack.length = 0;
+  if (undoStack.length > 50) undoStack.shift();
+  _updateUndoRedoBtns();
+}
+
+function _applySnapshot(snap) {
+  extractedPartials = snap;
+  editor.setPartials(snap);
+  if (viewer) {
+    viewer.setPartials(snap);
+    viewer.setKeepCount(snap.length > 0 ? getKeepCount() : 0);
+    viewer.selectPartial(-1);
+  }
+  _updateUndoRedoBtns();
+}
+
+function undo() {
+  if (!undoStack.length) return;
+  redoStack.push(JSON.parse(JSON.stringify(extractedPartials || [])));
+  _applySnapshot(undoStack.pop());
+}
+
+function redo() {
+  if (!redoStack.length) return;
+  undoStack.push(JSON.parse(JSON.stringify(extractedPartials || [])));
+  _applySnapshot(redoStack.pop());
+}
+
 const wavFile = document.getElementById('wavFile');
 const chooseFileBtn = document.getElementById('chooseFileBtn');
 const extractBtn = document.getElementById('extractBtn');
@@ -83,6 +122,7 @@ editor.onPartialDeleted = () => {
   if (viewer && extractedPartials)
     viewer.setKeepCount(extractedPartials.length > 0 ? getKeepCount() : 0);
 };
+editor.onBeforeChange = pushUndo;
 
 // Initialize audio context
 function initAudioContext() {
@@ -111,6 +151,7 @@ function loadAudioBuffer(buffer, label) {
     editor.setViewer(viewer);
     viewer.onPartialSelect = (i) => editor.onPartialSelect(i);
     viewer.onRender        = ()  => editor.onRender();
+    viewer.onBeforeChange  = pushUndo;
     if (label.startsWith('Test WAV')) validateTestWAVPeaks(stftCache);
   }, 10);
 }
@@ -213,6 +254,8 @@ function runExtraction() {
     }
     extractBtn.disabled = false;
     autoSpreadAllBtn.disabled = false;
+    document.getElementById('newPartialBtn').disabled = false;
+    undoStack.length = 0; redoStack.length = 0; _updateUndoRedoBtns();
   }, 50);
 }
 
@@ -221,6 +264,36 @@ extractBtn.addEventListener('click', () => {
   runExtraction();
 });
 
+function createNewPartial() {
+  if (!audioBuffer || !extractedPartials) return;
+  pushUndo();
+  const dur = audioBuffer.duration;
+  const newPartial = {
+    times:  [0, dur],
+    freqs:  [440, 440],
+    amps:   [1.0, 1.0],
+    phases: [0, 0],
+    muted:  false,
+    freqCurve: {
+      t0: 0,       t1: dur / 3,     t2: dur * 2 / 3, t3: dur,
+      v0: 440,     v1: 440,         v2: 440,          v3: 440,
+      a0: 1.0,     a1: 1.0,         a2: 1.0,          a3: 1.0,
+    },
+    replicas: { decay_alpha: 0.1, jitter: 0.05, spread_above: 0.02, spread_below: 0.02 },
+  };
+  extractedPartials.unshift(newPartial);
+  editor.setPartials(extractedPartials);
+  if (viewer) {
+    viewer.setPartials(extractedPartials);
+    viewer.setKeepCount(getKeepCount());
+    viewer.selectPartial(0);
+  }
+}
+
+document.getElementById('newPartialBtn').addEventListener('click', createNewPartial);
+document.getElementById('undoBtn').addEventListener('click', undo);
+document.getElementById('redoBtn').addEventListener('click', redo);
+
 autoSpreadAllBtn.addEventListener('click', () => {
   if (!extractedPartials || !stftCache) return;
   const fs = stftCache.fftSize;
@@ -353,6 +426,13 @@ function playSynthesized() {
 // Keyboard shortcuts
 document.addEventListener('keydown', (e) => {
   if (e.target.tagName === 'INPUT' || e.target.tagName === 'TEXTAREA') return;
+  if (e.ctrlKey && e.code === 'KeyZ' && !e.shiftKey) {
+    e.preventDefault(); undo(); return;
+  } else if (e.ctrlKey && (e.code === 'KeyY' || (e.code === 'KeyZ' && e.shiftKey))) {
+    e.preventDefault(); redo(); return;
+  } else if (e.code === 'KeyN' && !e.ctrlKey && !e.metaKey) {
+    e.preventDefault(); createNewPartial(); return;
+  }
   if (e.code === 'Digit1') {
     e.preventDefault();
     playSynthesized();