feat(mq_editor): partial selection, amp bezier editor, and editor.js refactor

- Click-to-select partials on canvas (proximity hit test on bezier)
- Right panel: peak freq/amp, time range, freq/amp bezier text inputs, mute/delete
- Selected partial renders on top with glow + larger control points
- Draggable freq curve control points on main canvas (grab/grabbing cursor)
- Amplitude bezier editor: 120px canvas below spectrogram, time-synced
  with main view zoom/scroll via viewer.onRender callback
- Amp edits live-affect synthesis (mq_synth.js already uses ampCurve)
- PartialEditor class in editor.js owns all editing logic; index.html
  wires it with 5 calls (setViewer, setPartials, onPartialSelect, onRender,
  onPartialDeleted)

handoff(Gemini): partial editing MVP complete. Next: freq curve drag polish
or export (.spec generation).

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

3 files changed, 678 insertions, 128 deletions

diff --git a/tools/mq_editor/editor.js b/tools/mq_editor/editor.js
new file mode 100644
index 0000000..e1e70c6
--- /dev/null
+++ b/tools/mq_editor/editor.js
@@ -0,0 +1,324 @@
+// Partial Editor
+// Property panel (right) and amplitude bezier editor (bottom) for selected partials
+
+class PartialEditor {
+  constructor() {
+    // DOM refs
+    this._propPanel = document.getElementById('partialProps');
+    this._noSelMsg  = document.getElementById('noSelMsg');
+    this._ampPanel  = document.getElementById('ampEditPanel');
+    this._ampCanvas = document.getElementById('ampEditCanvas');
+    this._ampTitle  = document.getElementById('ampEditTitle');
+    this._freqGrid  = document.getElementById('freqCurveGrid');
+    this._ampGrid   = document.getElementById('ampCurveGrid');
+    this._ampCtx    = this._ampCanvas ? this._ampCanvas.getContext('2d') : null;
+
+    // References set by host
+    this.viewer   = null;
+    this.partials = null;
+
+    // Callback: called after a partial is deleted so the host can update keepCount
+    this.onPartialDeleted = null;
+
+    // Private state
+    this._selectedIndex  = -1;
+    this._dragPointIndex = -1;
+    this._amp = { tMin: 0, tMax: 1, ampTop: 1 };
+
+    this._setupButtons();
+    this._setupAmpDrag();
+  }
+
+  // --- Public API ---
+
+  setViewer(v)   { this.viewer   = v; }
+  setPartials(p) { this.partials = p; }
+
+  // Wire to viewer.onPartialSelect
+  onPartialSelect(index) {
+    this._selectedIndex = index;
+    this._updatePropPanel(index);
+    this._showAmpEditor(index);
+  }
+
+  // Wire to viewer.onRender — keeps amp editor in sync with zoom/scroll
+  onRender() {
+    this._renderAmpEditor();
+  }
+
+  // --- Property panel ---
+
+  _updatePropPanel(index) {
+    if (index < 0 || !this.partials || index >= this.partials.length) {
+      this._propPanel.style.display = 'none';
+      this._noSelMsg.style.display  = 'block';
+      return;
+    }
+
+    this._propPanel.style.display = 'block';
+    this._noSelMsg.style.display  = 'none';
+
+    const partial = this.partials[index];
+    const color   = this.viewer ? this.viewer.partialColor(index) : '#888';
+
+    document.getElementById('propTitle').textContent   = 'Partial #' + index;
+    document.getElementById('propSwatch').style.background = color;
+
+    let peakAmp = 0, peakIdx = 0;
+    for (let i = 0; i < partial.amps.length; ++i) {
+      if (partial.amps[i] > peakAmp) { peakAmp = partial.amps[i]; peakIdx = i; }
+    }
+    document.getElementById('propPeak').textContent =
+      partial.freqs[peakIdx].toFixed(1) + ' Hz  ' + peakAmp.toFixed(3);
+
+    const t0 = partial.freqCurve ? partial.freqCurve.t0 : partial.times[0];
+    const t3 = partial.freqCurve ? partial.freqCurve.t3 : partial.times[partial.times.length - 1];
+    document.getElementById('propTime').textContent =
+      t0.toFixed(3) + 's\u2013' + t3.toFixed(3) + 's';
+
+    const muteBtn = document.getElementById('mutePartialBtn');
+    muteBtn.textContent  = partial.muted ? 'Unmute' : 'Mute';
+    muteBtn.style.color  = partial.muted ? '#fa4' : '';
+
+    this._buildCurveGrid(this._freqGrid, partial, 'freqCurve', 'f', index);
+    this._buildCurveGrid(this._ampGrid,  partial, 'ampCurve',  'a', index);
+  }
+
+  _buildCurveGrid(grid, partial, curveKey, valueLabel, partialIndex) {
+    grid.innerHTML = '';
+    const curve = partial[curveKey];
+    if (!curve) { grid.style.color = '#444'; grid.textContent = 'none'; return; }
+
+    for (let i = 0; i < 4; ++i) {
+      const lbl    = document.createElement('span');
+      lbl.textContent = 'P' + i;
+
+      const tInput = document.createElement('input');
+      tInput.type  = 'number';
+      tInput.value = curve['t' + i].toFixed(4);
+      tInput.step  = '0.001';
+      tInput.title = 't' + i;
+      tInput.addEventListener('change', this._makeCurveUpdater(partialIndex, curveKey, 't', i));
+
+      const vInput = document.createElement('input');
+      vInput.type  = 'number';
+      vInput.value = curveKey === 'freqCurve' ? curve['v' + i].toFixed(2) : curve['v' + i].toFixed(4);
+      vInput.step  = curveKey === 'freqCurve' ? '1' : '0.0001';
+      vInput.title = valueLabel + i;
+      vInput.addEventListener('change', this._makeCurveUpdater(partialIndex, curveKey, 'v', i));
+
+      grid.appendChild(lbl);
+      grid.appendChild(tInput);
+      grid.appendChild(vInput);
+    }
+  }
+
+  _makeCurveUpdater(partialIndex, curveKey, field, pointIndex) {
+    return (e) => {
+      if (!this.partials) return;
+      const val = parseFloat(e.target.value);
+      if (isNaN(val)) return;
+      this.partials[partialIndex][curveKey][field + pointIndex] = val;
+      if (this.viewer) this.viewer.render();
+    };
+  }
+
+  _setupButtons() {
+    document.getElementById('mutePartialBtn').addEventListener('click', () => {
+      if (this._selectedIndex < 0 || !this.partials) return;
+      const p = this.partials[this._selectedIndex];
+      p.muted = !p.muted;
+      if (this.viewer) this.viewer.render();
+      this._updatePropPanel(this._selectedIndex);
+    });
+
+    document.getElementById('deletePartialBtn').addEventListener('click', () => {
+      if (this._selectedIndex < 0 || !this.partials || !this.viewer) return;
+      this.partials.splice(this._selectedIndex, 1);
+      this.viewer.selectPartial(-1);
+      if (this.onPartialDeleted) this.onPartialDeleted();
+    });
+  }
+
+  // --- Amplitude bezier editor ---
+
+  _showAmpEditor(index) {
+    if (index < 0 || !this.partials || index >= this.partials.length) {
+      this._ampPanel.style.display = 'none';
+      return;
+    }
+    this._ampPanel.style.display = 'block';
+    const color = this.viewer ? this.viewer.partialColor(index) : '#888';
+    this._ampTitle.textContent   = 'Partial #' + index;
+    this._ampTitle.style.color   = color;
+    this._renderAmpEditor();
+  }
+
+  _renderAmpEditor() {
+    if (this._selectedIndex < 0 || !this.partials || !this._ampCtx) return;
+    const partial = this.partials[this._selectedIndex];
+    if (!partial) return;
+
+    const canvas = this._ampCanvas;
+    const ctx    = this._ampCtx;
+    const W = canvas.width, H = canvas.height;
+    const PADY = 10;
+
+    // Sync time range with viewer
+    const amp  = this._amp;
+    amp.tMin   = this.viewer ? this.viewer.t_view_min : 0;
+    amp.tMax   = this.viewer ? this.viewer.t_view_max : 1;
+    amp.ampTop = Math.max(partial.amps.reduce((m, v) => Math.max(m, v), 0), 0.001) * 1.3;
+
+    ctx.fillStyle = '#0e0e0e';
+    ctx.fillRect(0, 0, W, H);
+
+    // Horizontal grid (0, 25, 50, 75, 100% of ampTop)
+    ctx.lineWidth = 1;
+    ctx.font = '9px monospace';
+    for (let k = 0; k <= 4; ++k) {
+      const a = amp.ampTop * k / 4;
+      const y = this._ampToY(a);
+      ctx.strokeStyle = k === 0 ? '#2a2a2a' : '#1a1a1a';
+      ctx.beginPath(); ctx.moveTo(0, y); ctx.lineTo(W, y); ctx.stroke();
+      ctx.fillStyle = '#383838';
+      ctx.fillText(a.toFixed(3), W - 40, y - 2);
+    }
+
+    // Vertical time grid (matching main view step)
+    if (this.viewer) {
+      const step = this.viewer.getAxisStep(amp.tMax - amp.tMin);
+      let t = Math.ceil(amp.tMin / step) * step;
+      ctx.strokeStyle = '#1a1a1a';
+      ctx.fillStyle   = '#383838';
+      while (t <= amp.tMax) {
+        const x = this._tToX(t);
+        ctx.beginPath(); ctx.moveTo(x, 0); ctx.lineTo(x, H); ctx.stroke();
+        ctx.fillText(t.toFixed(2) + 's', x + 2, H - 2);
+        t += step;
+      }
+    }
+
+    // Raw amp data (faint dots)
+    ctx.fillStyle = '#2e2e2e';
+    for (let i = 0; i < partial.times.length; ++i) {
+      const x = this._tToX(partial.times[i]);
+      if (x < -2 || x > W + 2) continue;
+      ctx.fillRect(x - 1, this._ampToY(partial.amps[i]) - 1, 2, 2);
+    }
+
+    // Bezier curve
+    const curve = partial.ampCurve;
+    if (!curve) return;
+
+    const color = this.viewer ? this.viewer.partialColor(this._selectedIndex) : '#f44';
+    ctx.strokeStyle = color;
+    ctx.lineWidth   = 2;
+    ctx.beginPath();
+    let started = false;
+    for (let i = 0; i <= 120; ++i) {
+      const t = curve.t0 + (curve.t3 - curve.t0) * i / 120;
+      const x = this._tToX(t);
+      if (x < -1 || x > W + 1) { started = false; continue; }
+      const y = this._ampToY(evalBezier(curve, t));
+      if (!started) { ctx.moveTo(x, y); started = true; } else ctx.lineTo(x, y);
+    }
+    ctx.stroke();
+
+    // Control points
+    for (let i = 0; i < 4; ++i) {
+      const x = this._tToX(curve['t' + i]);
+      const y = this._ampToY(curve['v' + i]);
+      ctx.fillStyle = color;
+      ctx.beginPath();
+      ctx.arc(x, y, 6, 0, 2 * Math.PI);
+      ctx.fill();
+      ctx.strokeStyle = '#fff';
+      ctx.lineWidth   = 1.5;
+      ctx.stroke();
+      ctx.fillStyle = '#888';
+      ctx.font      = '9px monospace';
+      ctx.fillText('P' + i, x + 8, y - 4);
+    }
+  }
+
+  _setupAmpDrag() {
+    const canvas = this._ampCanvas;
+    if (!canvas) return;
+
+    canvas.addEventListener('mousedown', (e) => {
+      if (this._selectedIndex < 0 || !this.partials) return;
+      const partial = this.partials[this._selectedIndex];
+      if (!partial || !partial.ampCurve) return;
+      const rect  = canvas.getBoundingClientRect();
+      const x = e.clientX - rect.left, y = e.clientY - rect.top;
+      const curve = partial.ampCurve;
+      for (let i = 0; i < 4; ++i) {
+        if (Math.hypot(this._tToX(curve['t' + i]) - x, this._ampToY(curve['v' + i]) - y) <= 8) {
+          this._dragPointIndex = i;
+          canvas.style.cursor  = 'grabbing';
+          e.preventDefault();
+          return;
+        }
+      }
+    });
+
+    canvas.addEventListener('mousemove', (e) => {
+      const rect  = canvas.getBoundingClientRect();
+      const x = e.clientX - rect.left, y = e.clientY - rect.top;
+
+      if (this._dragPointIndex >= 0) {
+        const curve = this.partials[this._selectedIndex].ampCurve;
+        const i     = this._dragPointIndex;
+        curve['t' + i] = Math.max(0, Math.min(this.viewer ? this.viewer.t_max : 1e6, this._xToT(x)));
+        curve['v' + i] = Math.max(0, this._yToAmp(y));
+        this._renderAmpEditor();
+        if (this.viewer) this.viewer.render();
+        e.preventDefault();
+        return;
+      }
+
+      // Cursor hint
+      if (this._selectedIndex >= 0 && this.partials) {
+        const curve = this.partials[this._selectedIndex]?.ampCurve;
+        if (curve) {
+          let near = false;
+          for (let i = 0; i < 4; ++i) {
+            if (Math.hypot(this._tToX(curve['t' + i]) - x, this._ampToY(curve['v' + i]) - y) <= 8) {
+              near = true; break;
+            }
+          }
+          canvas.style.cursor = near ? 'grab' : 'crosshair';
+        }
+      }
+    });
+
+    canvas.addEventListener('mouseup', () => {
+      if (this._dragPointIndex >= 0) {
+        this._dragPointIndex = -1;
+        canvas.style.cursor  = 'crosshair';
+        this._updatePropPanel(this._selectedIndex); // sync text inputs
+      }
+    });
+  }
+
+  // --- Coordinate helpers (amp canvas) ---
+
+  _tToX(t) {
+    return (t - this._amp.tMin) / (this._amp.tMax - this._amp.tMin) * this._ampCanvas.width;
+  }
+
+  _xToT(x) {
+    return this._amp.tMin + (x / this._ampCanvas.width) * (this._amp.tMax - this._amp.tMin);
+  }
+
+  _ampToY(a) {
+    const PADY = 10, H = this._ampCanvas.height;
+    return PADY + (1 - a / this._amp.ampTop) * (H - 2 * PADY);
+  }
+
+  _yToAmp(y) {
+    const PADY = 10, H = this._ampCanvas.height;
+    return (1 - (y - PADY) / (H - 2 * PADY)) * this._amp.ampTop;
+  }
+}
diff --git a/tools/mq_editor/index.html b/tools/mq_editor/index.html
index 60076b3..c5902a7 100644
--- a/tools/mq_editor/index.html
+++ b/tools/mq_editor/index.html
@@ -73,12 +73,16 @@
       border: 1px solid #555;
       border-radius: 4px;
       padding: 12px;
-      min-width: 160px;
+      min-width: 220px;
+      max-width: 220px;
+      max-height: 600px;
+      overflow-y: auto;
       display: flex;
       flex-direction: column;
-      gap: 10px;
+      gap: 6px;
+      box-sizing: border-box;
     }
-    .right-panel .panel-title {
+    .panel-title {
       font-size: 11px;
       color: #888;
       text-transform: uppercase;
@@ -86,6 +90,9 @@
       border-bottom: 1px solid #444;
       padding-bottom: 6px;
       margin-bottom: 2px;
+      display: flex;
+      align-items: center;
+      gap: 6px;
     }
     .right-panel label {
       display: flex;
@@ -95,6 +102,61 @@
       cursor: pointer;
       font-size: 13px;
     }
+    /* Partial properties */
+    .prop-row {
+      display: flex;
+      justify-content: space-between;
+      align-items: baseline;
+      font-size: 12px;
+      padding: 1px 0;
+    }
+    .prop-label { color: #777; font-size: 11px; }
+    .prop-section {
+      font-size: 10px;
+      color: #666;
+      text-transform: uppercase;
+      letter-spacing: 0.5px;
+      margin-top: 6px;
+      margin-bottom: 2px;
+    }
+    .curve-grid {
+      display: grid;
+      grid-template-columns: 18px 1fr 1fr;
+      gap: 2px 3px;
+      align-items: center;
+    }
+    .curve-grid span { color: #666; font-size: 10px; }
+    .curve-grid input[type="number"] {
+      width: 100%;
+      background: #333;
+      color: #ccc;
+      border: 1px solid #444;
+      padding: 1px 3px;
+      border-radius: 2px;
+      font-size: 10px;
+      font-family: monospace;
+      box-sizing: border-box;
+    }
+    .curve-grid input[type="number"]:focus {
+      border-color: #666;
+      outline: none;
+    }
+    .partial-actions {
+      display: flex;
+      gap: 4px;
+      margin-top: 6px;
+    }
+    .partial-actions button {
+      flex: 1;
+      padding: 3px 6px;
+      font-size: 11px;
+      margin: 0;
+    }
+    .synth-section {
+      border-top: 1px solid #444;
+      padding-top: 8px;
+      margin-top: auto;
+    }
     #status {
       margin-top: 10px;
       padding: 8px;
@@ -135,21 +197,62 @@
   </div>
 
   <div class="main-area">
-    <div style="position: relative; flex-shrink: 0;">
-      <canvas id="canvas" width="1400" height="600"></canvas>
-      <canvas id="cursorCanvas" width="1400" height="600" style="position:absolute;top:0;left:0;pointer-events:none;"></canvas>
+    <div style="display:flex; flex-direction:column; gap:6px; flex-shrink:0;">
+      <div style="position: relative;">
+        <canvas id="canvas" width="1400" height="600"></canvas>
+        <canvas id="cursorCanvas" width="1400" height="600" style="position:absolute;top:0;left:0;pointer-events:none;"></canvas>
 
-      <!-- Mini spectrum viewer (bottom-right overlay) -->
-      <div id="spectrumViewer" style="position: absolute; bottom: 10px; right: 10px; width: 400px; height: 100px; background: rgba(30, 30, 30, 0.9); border: 1px solid #555; border-radius: 3px; pointer-events: none;">
-        <canvas id="spectrumCanvas" width="400" height="100"></canvas>
+        <!-- Mini spectrum viewer (bottom-right overlay) -->
+        <div id="spectrumViewer" style="position: absolute; bottom: 10px; right: 10px; width: 400px; height: 100px; background: rgba(30, 30, 30, 0.9); border: 1px solid #555; border-radius: 3px; pointer-events: none;">
+          <canvas id="spectrumCanvas" width="400" height="100"></canvas>
+        </div>
+      </div>
+
+      <!-- Amplitude bezier editor (shown when partial selected) -->
+      <div id="ampEditPanel" style="display:none;">
+        <div style="font-size:10px; color:#555; padding:2px 0 3px 1px; display:flex; align-items:center; gap:10px; text-transform:uppercase; letter-spacing:0.5px;">
+          <span>Amplitude</span>
+          <span id="ampEditTitle" style="color:#777; text-transform:none; letter-spacing:0;"></span>
+          <span style="color:#333; text-transform:none; letter-spacing:0;">drag control points · Esc to deselect</span>
+        </div>
+        <canvas id="ampEditCanvas" width="1400" height="120" style="border:1px solid #2a2a2a; background:#0e0e0e; cursor:crosshair; display:block;"></canvas>
       </div>
     </div>
 
     <div class="right-panel">
-      <div class="panel-title">Synthesis</div>
-      <label><input type="checkbox" id="integratePhase" checked> Integrate phase</label>
-      <label><input type="checkbox" id="disableJitter"> Disable jitter</label>
-      <label><input type="checkbox" id="disableSpread"> Disable spread</label>
+      <!-- Partial properties (visible when a partial is selected) -->
+      <div id="partialProps" style="display:none;">
+        <div class="panel-title">
+          <span id="propTitle">Partial #—</span>
+          <span id="propSwatch" style="display:inline-block;width:10px;height:10px;border-radius:2px;flex-shrink:0;"></span>
+        </div>
+        <div class="prop-row">
+          <span class="prop-label">Peak</span>
+          <span id="propPeak">—</span>
+        </div>
+        <div class="prop-row">
+          <span class="prop-label">Time</span>
+          <span id="propTime">—</span>
+        </div>
+        <div class="prop-section">Freq Curve</div>
+        <div class="curve-grid" id="freqCurveGrid"></div>
+        <div class="prop-section">Amp Curve</div>
+        <div class="curve-grid" id="ampCurveGrid"></div>
+        <div class="partial-actions">
+          <button id="mutePartialBtn">Mute</button>
+          <button id="deletePartialBtn">Delete</button>
+        </div>
+      </div>
+
+      <div id="noSelMsg" style="color:#555;font-size:11px;padding:2px 0;">Click a partial to select</div>
+
+      <!-- Synthesis options (always at bottom) -->
+      <div class="synth-section">
+        <div class="panel-title">Synthesis</div>
+        <label><input type="checkbox" id="integratePhase" checked> Integrate phase</label>
+        <label><input type="checkbox" id="disableJitter"> Disable jitter</label>
+        <label><input type="checkbox" id="disableSpread"> Disable spread</label>
+      </div>
     </div>
   </div>
 
@@ -161,6 +264,7 @@
   <script src="mq_extract.js"></script>
   <script src="mq_synth.js"></script>
   <script src="viewer.js"></script>
+  <script src="editor.js"></script>
   <script>
     let audioBuffer = null;
     let viewer = null;
@@ -193,6 +297,13 @@
       if (viewer && extractedPartials) viewer.setKeepCount(getKeepCount());
     });
 
+    // --- Editor ---
+    const editor = new PartialEditor();
+    editor.onPartialDeleted = () => {
+      if (viewer && extractedPartials)
+        viewer.setKeepCount(extractedPartials.length > 0 ? getKeepCount() : 0);
+    };
+
     // Initialize audio context
     function initAudioContext() {
       if (!audioContext) {
@@ -213,6 +324,9 @@
         stftCache = new STFTCache(signal, audioBuffer.sampleRate, fftSize, Math.max(64, parseInt(hopSize.value) || 64));
         setStatus(`${label} — ${audioBuffer.duration.toFixed(2)}s, ${audioBuffer.sampleRate}Hz, ${audioBuffer.numberOfChannels}ch (${stftCache.getNumFrames()} frames cached)`, 'info');
         viewer = new SpectrogramViewer(canvas, audioBuffer, stftCache);
+        editor.setViewer(viewer);
+        viewer.onPartialSelect = (i) => editor.onPartialSelect(i);
+        viewer.onRender        = ()  => editor.onRender();
         if (label.startsWith('Test WAV')) validateTestWAVPeaks(stftCache);
       }, 10);
     }
@@ -296,10 +410,12 @@
           });
 
           extractedPartials = result.partials;
+          editor.setPartials(result.partials);
           viewer.setFrames(result.frames);
           setStatus(`Extracted ${result.partials.length} partials`, 'info');
           viewer.setPartials(result.partials);
           viewer.setKeepCount(getKeepCount());
+          viewer.selectPartial(-1);
 
         } catch (err) {
           setStatus('Extraction error: ' + err.message, 'error');
@@ -384,8 +500,8 @@
       setStatus('Synthesizing...', 'info');
 
       const keepCount = getKeepCount();
-      const partialsToUse = extractedPartials.slice(0, keepCount);
-      setStatus(`Synthesizing ${keepCount}/${extractedPartials.length} partials (${keepPct.value}%)...`, 'info');
+      const partialsToUse = extractedPartials.slice(0, keepCount).filter(p => !p.muted);
+      setStatus(`Synthesizing ${partialsToUse.length}/${extractedPartials.length} partials (${keepPct.value}%)...`, 'info');
 
       const integratePhase = document.getElementById('integratePhase').checked;
       const disableJitter  = document.getElementById('disableJitter').checked;
@@ -399,7 +515,7 @@
 
       const synthBuffer = audioContext.createBuffer(1, pcm.length, audioBuffer.sampleRate);
       synthBuffer.getChannelData(0).set(pcm);
-      playAudioBuffer(synthBuffer, `Playing synthesized (${keepCount}/${extractedPartials.length} partials, ${keepPct.value}%)...`);
+      playAudioBuffer(synthBuffer, `Playing synthesized (${partialsToUse.length}/${extractedPartials.length} partials, ${keepPct.value}%)...`);
     }
 
     // Keyboard shortcuts
@@ -422,6 +538,8 @@
           viewer.showSynthFFT = !viewer.showSynthFFT;
           viewer.renderSpectrum();
         }
+      } else if (e.code === 'Escape') {
+        if (viewer) viewer.selectPartial(-1);
       }
     });
 
diff --git a/tools/mq_editor/viewer.js b/tools/mq_editor/viewer.js
index 7f6e862..c158536 100644
--- a/tools/mq_editor/viewer.js
+++ b/tools/mq_editor/viewer.js
@@ -48,6 +48,12 @@ class SpectrogramViewer {
     this.showSynthFFT = false; // Toggle: false=original, true=synth
     this.synthStftCache = null;
 
+    // Selection and editing
+    this.selectedPartial = -1;
+    this.dragState = null; // {pointIndex: 0-3}
+    this.onPartialSelect = null; // callback(index)
+    this.onRender = null; // callback() called after each render (for synced panels)
+
     // Setup event handlers
     this.setupMouseHandlers();
 
@@ -153,6 +159,47 @@ class SpectrogramViewer {
     return this.stftCache.getMagnitudeDB(time, freq);
   }
 
+  selectPartial(index) {
+    this.selectedPartial = index;
+    this.render();
+    if (this.onPartialSelect) this.onPartialSelect(index);
+  }
+
+  // Hit-test bezier curves: returns index of nearest partial within threshold
+  hitTestPartial(x, y) {
+    const THRESH = 10;
+    let bestIdx = -1, bestDist = THRESH;
+    for (let p = 0; p < this.partials.length; ++p) {
+      const curve = this.partials[p].freqCurve;
+      if (!curve) continue;
+      for (let i = 0; i <= 50; ++i) {
+        const t = curve.t0 + (curve.t3 - curve.t0) * i / 50;
+        if (t < this.t_view_min || t > this.t_view_max) continue;
+        const f = evalBezier(curve, t);
+        if (f < this.freqStart || f > this.freqEnd) continue;
+        const px = this.timeToX(t), py = this.freqToY(f);
+        const dist = Math.hypot(px - x, py - y);
+        if (dist < bestDist) { bestDist = dist; bestIdx = p; }
+      }
+    }
+    return bestIdx;
+  }
+
+  // Hit-test control points of a specific partial's freqCurve
+  hitTestControlPoint(x, y, partial) {
+    const curve = partial.freqCurve;
+    if (!curve) return -1;
+    const THRESH = 8;
+    for (let i = 0; i < 4; ++i) {
+      const t = curve['t' + i], v = curve['v' + i];
+      if (t < this.t_view_min || t > this.t_view_max) continue;
+      if (v < this.freqStart || v > this.freqEnd) continue;
+      const px = this.timeToX(t), py = this.freqToY(v);
+      if (Math.hypot(px - x, py - y) <= THRESH) return i;
+    }
+    return -1;
+  }
+
   // --- Render ---
 
   render() {
@@ -162,6 +209,100 @@ class SpectrogramViewer {
     this.drawAxes();
     this.drawPlayhead();
     this.renderSpectrum();
+    if (this.onRender) this.onRender();
+  }
+
+  renderPartials() {
+    for (let p = 0; p < this.partials.length; ++p) {
+      if (p === this.selectedPartial) continue; // draw selected last (on top)
+      this._renderPartial(p, this.partials[p], false);
+    }
+    if (this.selectedPartial >= 0 && this.selectedPartial < this.partials.length) {
+      this._renderPartial(this.selectedPartial, this.partials[this.selectedPartial], true);
+    }
+    this.ctx.globalAlpha = 1.0;
+    this.ctx.shadowBlur = 0;
+  }
+
+  _renderPartial(p, partial, isSelected) {
+    const {ctx} = this;
+    const color = this.partialColor(p);
+    let alpha = isSelected ? 1.0 : (p < this.keepCount ? 1.0 : 0.5);
+    if (partial.muted && !isSelected) alpha = 0.15;
+    ctx.globalAlpha = alpha;
+
+    // Raw trajectory
+    ctx.strokeStyle = color + '44';
+    ctx.lineWidth = 1;
+    ctx.beginPath();
+    let started = false;
+    for (let i = 0; i < partial.times.length; ++i) {
+      const t = partial.times[i];
+      const f = partial.freqs[i];
+      if (t < this.t_view_min || t > this.t_view_max) continue;
+      if (f < this.freqStart || f > this.freqEnd) continue;
+      const x = this.timeToX(t);
+      const y = this.freqToY(f);
+      if (!started) { ctx.moveTo(x, y); started = true; } else ctx.lineTo(x, y);
+    }
+    if (started) ctx.stroke();
+
+    // Bezier curve
+    if (partial.freqCurve) {
+      const curve = partial.freqCurve;
+      if (isSelected) { ctx.shadowColor = color; ctx.shadowBlur = 8; }
+      ctx.strokeStyle = color;
+      ctx.lineWidth = isSelected ? 3 : 2;
+      ctx.beginPath();
+      started = false;
+      for (let i = 0; i <= 50; ++i) {
+        const t = curve.t0 + (curve.t3 - curve.t0) * i / 50;
+        const freq = evalBezier(curve, t);
+        if (t < this.t_view_min || t > this.t_view_max) continue;
+        if (freq < this.freqStart || freq > this.freqEnd) continue;
+        const x = this.timeToX(t);
+        const y = this.freqToY(freq);
+        if (!started) { ctx.moveTo(x, y); started = true; } else ctx.lineTo(x, y);
+      }
+      if (started) ctx.stroke();
+      if (isSelected) ctx.shadowBlur = 0;
+
+      ctx.fillStyle = color;
+      const cpR = isSelected ? 6 : 4;
+      this.drawControlPoint(curve.t0, curve.v0, cpR);
+      this.drawControlPoint(curve.t1, curve.v1, cpR);
+      this.drawControlPoint(curve.t2, curve.v2, cpR);
+      this.drawControlPoint(curve.t3, curve.v3, cpR);
+    }
+  }
+
+  renderPeaks() {
+    const {ctx, frames} = this;
+    if (!frames || frames.length === 0) return;
+
+    ctx.fillStyle = '#fff';
+    for (const frame of frames) {
+      const t = frame.time;
+      if (t < this.t_view_min || t > this.t_view_max) continue;
+      const x = this.timeToX(t);
+      for (const peak of frame.peaks) {
+        if (peak.freq < this.freqStart || peak.freq > this.freqEnd) continue;
+        ctx.fillRect(x - 1, this.freqToY(peak.freq) - 1, 3, 3);
+      }
+    }
+  }
+
+  drawControlPoint(t, v, radius = 4) {
+    if (t < this.t_view_min || t > this.t_view_max) return;
+    if (v < this.freqStart || v > this.freqEnd) return;
+    const x = this.timeToX(t);
+    const y = this.freqToY(v);
+    this.ctx.beginPath();
+    this.ctx.arc(x, y, radius, 0, 2 * Math.PI);
+    this.ctx.fill();
+    this.ctx.strokeStyle = '#fff';
+    this.ctx.lineWidth = 1;
+    this.ctx.stroke();
   }
 
   drawMouseCursor(x) {
@@ -243,118 +384,6 @@ class SpectrogramViewer {
     }
   }
 
-  renderPartials() {
-    const {ctx, partials} = this;
-
-    for (let p = 0; p < partials.length; ++p) {
-      const partial = partials[p];
-      const color = this.partialColor(p);
-      ctx.globalAlpha = p < this.keepCount ? 1.0 : 0.5;
-
-      // Raw trajectory
-      ctx.strokeStyle = color + '44';
-      ctx.lineWidth = 1;
-      ctx.beginPath();
-      let started = false;
-      for (let i = 0; i < partial.times.length; ++i) {
-        const t = partial.times[i];
-        const f = partial.freqs[i];
-        if (t < this.t_view_min || t > this.t_view_max) continue;
-        if (f < this.freqStart || f > this.freqEnd) continue;
-        const x = this.timeToX(t);
-        const y = this.freqToY(f);
-        if (!started) { ctx.moveTo(x, y); started = true; } else ctx.lineTo(x, y);
-      }
-      if (started) ctx.stroke();
-
-      // Bezier curve
-      if (partial.freqCurve) {
-        ctx.strokeStyle = color;
-        ctx.lineWidth = 2;
-        ctx.beginPath();
-        const curve = partial.freqCurve;
-        started = false;
-        for (let i = 0; i <= 50; ++i) {
-          const t = curve.t0 + (curve.t3 - curve.t0) * i / 50;
-          const freq = evalBezier(curve, t);
-          if (t < this.t_view_min || t > this.t_view_max) continue;
-          if (freq < this.freqStart || freq > this.freqEnd) continue;
-          const x = this.timeToX(t);
-          const y = this.freqToY(freq);
-          if (!started) { ctx.moveTo(x, y); started = true; } else ctx.lineTo(x, y);
-        }
-        if (started) ctx.stroke();
-
-        ctx.fillStyle = color;
-        this.drawControlPoint(curve.t0, curve.v0);
-        this.drawControlPoint(curve.t1, curve.v1);
-        this.drawControlPoint(curve.t2, curve.v2);
-        this.drawControlPoint(curve.t3, curve.v3);
-      }
-    }
-
-    ctx.globalAlpha = 1.0;
-  }
-
-  renderPeaks() {
-    const {ctx, frames} = this;
-    if (!frames || frames.length === 0) return;
-
-    ctx.fillStyle = '#fff';
-    for (const frame of frames) {
-      const t = frame.time;
-      if (t < this.t_view_min || t > this.t_view_max) continue;
-      const x = this.timeToX(t);
-      for (const peak of frame.peaks) {
-        if (peak.freq < this.freqStart || peak.freq > this.freqEnd) continue;
-        ctx.fillRect(x - 1, this.freqToY(peak.freq) - 1, 3, 3);
-      }
-    }
-  }
-
-  drawControlPoint(t, v) {
-    if (t < this.t_view_min || t > this.t_view_max) return;
-    if (v < this.freqStart || v > this.freqEnd) return;
-    const x = this.timeToX(t);
-    const y = this.freqToY(v);
-    this.ctx.beginPath();
-    this.ctx.arc(x, y, 4, 0, 2 * Math.PI);
-    this.ctx.fill();
-    this.ctx.strokeStyle = '#fff';
-    this.ctx.lineWidth = 1;
-    this.ctx.stroke();
-  }
-
-  drawAxes() {
-    const {ctx, canvas} = this;
-    const width = canvas.width;
-    const height = canvas.height;
-
-    ctx.strokeStyle = '#666';
-    ctx.fillStyle = '#aaa';
-    ctx.font = '11px monospace';
-    ctx.lineWidth = 1;
-
-    // Time axis
-    const timeDuration = this.t_view_max - this.t_view_min;
-    const timeStep = this.getAxisStep(timeDuration);
-    let t = Math.ceil(this.t_view_min / timeStep) * timeStep;
-    while (t <= this.t_view_max) {
-      const x = this.timeToX(t);
-      ctx.beginPath(); ctx.moveTo(x, 0); ctx.lineTo(x, height); ctx.stroke();
-      ctx.fillText(t.toFixed(2) + 's', x + 2, height - 4);
-      t += timeStep;
-    }
-
-    // Frequency axis (log-spaced ticks)
-    for (const f of [20, 50, 100, 200, 500, 1000, 2000, 5000, 10000, 16000]) {
-      if (f < this.freqStart || f > this.freqEnd) continue;
-      const y = this.freqToY(f);
-      ctx.beginPath(); ctx.moveTo(0, y); ctx.lineTo(width, y); ctx.stroke();
-      ctx.fillText((f >= 1000 ? (f/1000).toFixed(0) + 'k' : f.toFixed(0)) + 'Hz', 2, y - 2);
-    }
-  }
-
   renderSpectrum() {
     if (!this.spectrumCtx || !this.stftCache) return;
 
@@ -464,11 +493,44 @@ class SpectrogramViewer {
   setupMouseHandlers() {
     const {canvas, tooltip} = this;
 
+    canvas.addEventListener('mousedown', (e) => {
+      const rect = canvas.getBoundingClientRect();
+      const x = e.clientX - rect.left;
+      const y = e.clientY - rect.top;
+
+      // Check control point drag on selected partial
+      if (this.selectedPartial >= 0 && this.selectedPartial < this.partials.length) {
+        const ptIdx = this.hitTestControlPoint(x, y, this.partials[this.selectedPartial]);
+        if (ptIdx >= 0) {
+          this.dragState = { pointIndex: ptIdx };
+          canvas.style.cursor = 'grabbing';
+          e.preventDefault();
+          return;
+        }
+      }
+
+      // Otherwise: select partial by click
+      const idx = this.hitTestPartial(x, y);
+      this.selectPartial(idx);
+    });
+
     canvas.addEventListener('mousemove', (e) => {
       const rect = canvas.getBoundingClientRect();
       const x = e.clientX - rect.left;
       const y = e.clientY - rect.top;
 
+      if (this.dragState) {
+        const t = Math.max(0, Math.min(this.t_max, this.canvasToTime(x)));
+        const v = Math.max(this.freqStart, Math.min(this.freqEnd, this.canvasToFreq(y)));
+        const partial = this.partials[this.selectedPartial];
+        const i = this.dragState.pointIndex;
+        partial.freqCurve['t' + i] = t;
+        partial.freqCurve['v' + i] = v;
+        this.render();
+        e.preventDefault();
+        return;
+      }
+
       this.mouseX = x;
       this.drawMouseCursor(x);
 
@@ -481,6 +543,14 @@ class SpectrogramViewer {
         this.renderSpectrum();
       }
 
+      // Cursor hint for control points
+      if (this.selectedPartial >= 0 && this.selectedPartial < this.partials.length) {
+        const ptIdx = this.hitTestControlPoint(x, y, this.partials[this.selectedPartial]);
+        canvas.style.cursor = ptIdx >= 0 ? 'grab' : 'crosshair';
+      } else {
+        canvas.style.cursor = 'crosshair';
+      }
+
       tooltip.style.left = (e.clientX + 10) + 'px';
       tooltip.style.top  = (e.clientY + 10) + 'px';
       tooltip.style.display = 'block';
@@ -493,6 +563,14 @@ class SpectrogramViewer {
       tooltip.style.display = 'none';
     });
 
+    canvas.addEventListener('mouseup', () => {
+      if (this.dragState) {
+        this.dragState = null;
+        canvas.style.cursor = 'crosshair';
+        if (this.onPartialSelect) this.onPartialSelect(this.selectedPartial);
+      }
+    });
+
     canvas.addEventListener('wheel', (e) => {
       e.preventDefault();
       const delta = e.deltaY !== 0 ? e.deltaY : e.deltaX;
@@ -529,6 +607,36 @@ class SpectrogramViewer {
     for (const step of steps) { if (step >= targetStep) return step; }
     return steps[steps.length - 1];
   }
+
+  drawAxes() {
+    const {ctx, canvas} = this;
+    const width = canvas.width;
+    const height = canvas.height;
+
+    ctx.strokeStyle = '#666';
+    ctx.fillStyle = '#aaa';
+    ctx.font = '11px monospace';
+    ctx.lineWidth = 1;
+
+    // Time axis
+    const timeDuration = this.t_view_max - this.t_view_min;
+    const timeStep = this.getAxisStep(timeDuration);
+    let t = Math.ceil(this.t_view_min / timeStep) * timeStep;
+    while (t <= this.t_view_max) {
+      const x = this.timeToX(t);
+      ctx.beginPath(); ctx.moveTo(x, 0); ctx.lineTo(x, height); ctx.stroke();
+      ctx.fillText(t.toFixed(2) + 's', x + 2, height - 4);
+      t += timeStep;
+    }
+
+    // Frequency axis (log-spaced ticks)
+    for (const f of [20, 50, 100, 200, 500, 1000, 2000, 5000, 10000, 16000]) {
+      if (f < this.freqStart || f > this.freqEnd) continue;
+      const y = this.freqToY(f);
+      ctx.beginPath(); ctx.moveTo(0, y); ctx.lineTo(width, y); ctx.stroke();
+      ctx.fillText((f >= 1000 ? (f/1000).toFixed(0) + 'k' : f.toFixed(0)) + 'Hz', 2, y - 2);
+    }
+  }
 }
 
 // Bezier evaluation (shared utility)