Fix subvariation display, progress bar, and linked-instrument discard

- ast-parser: read for_value= prop for sub-variations (was always null,
  causing fallback to positional "subvariation N" label)
- StatusPoller: calculate progress from currently_rendered_notes /
  notes_in_total; show remaining_time string from status.json
- ShapeEditor/EnvelopeEditor: pass { undo } through onChange so callers
  can revert in-place mutations
- PaneFO: makeChangeHandler stashes undo from info arg; discardEdit
  calls undo() before clearing pendingEdit; depends_on handler provides
  its own undo for the inline node.dependsOn mutation

static/ast-parser.js

@@ -212,7 +212,7 @@ function buildInstrument(node) {
 function buildVariation(node) {
     const v = {
         type: 'variation',
-        dependsOn: node.props.depends_on ?? null,
+        dependsOn: node.props.depends_on ?? node.props.for_value ?? null,
         basicProperties: null,
         labelSpecs: [],
         subvariations: [],

static/components/EnvelopeEditor.js

@@ -24,12 +24,9 @@ export const EnvelopeEditor = {
     setup(props) {
         function toggle(section) {
             const bp = props.basicProperties;
-            if (bp[section]) {
+            const old = bp[section];
-                bp[section] = null;
+            bp[section] = old ? null : defaultShape(section);
-            } else {
+            props.onChange?.({ undo: () => { bp[section] = old; } });
-                bp[section] = defaultShape(section);
-            }
-            props.onChange?.();
         }
 
         return () => {
@@ -57,7 +54,7 @@ export const EnvelopeEditor = {
                         ? h('div', { class: disabled ? 'se-envelope-disabled' : null }, [
                             h(ShapeEditor, {
                                 shape: bp[key],
-                                onChange: props.onChange,
+                                onChange: info => props.onChange?.(info),
                             }),
                           ])
                         : null,

static/components/PaneFO.js

@@ -39,11 +39,11 @@ export const PaneFO = {
 
         // Returns a change handler that intercepts the first edit to a linked
         // instrument and shows the embed-or-discard modal before applying it.
+        // `info` may carry { undo } forwarded from ShapeEditor / EnvelopeEditor.
         function makeChangeHandler(instr, apply) {
-            return () => {
+            return (info) => {
                 if (instr.isLinked && !instr.isDirty) {
-                    // Stash the apply callback and show the modal.
+                    pendingEdit.value = { instr, apply, undo: info?.undo };
-                    pendingEdit.value = { instr, apply };
                 } else {
                     apply();
                     instr.isDirty = true;
@@ -62,6 +62,7 @@ export const PaneFO = {
         }
 
         function discardEdit() {
+            pendingEdit.value?.undo?.();
             pendingEdit.value = null;
         }
 
@@ -104,8 +105,13 @@ export const PaneFO = {
                 children.push(
                     h('h4', { style: 'margin:0 0 0.5rem' }, 'Variation'),
                     h(ObjectExtended, { fields: variationFields(node), onChange: ({ key, value }) => {
-                        if (key === 'depends_on') node.dependsOn = value;
+                        if (key === 'depends_on') {
-                        onChange();
+                            const old = node.dependsOn;
+                            node.dependsOn = value;
+                            onChange({ undo: () => { node.dependsOn = old; } });
+                        } else {
+                            onChange({});
+                        }
                     }}),
                     node.basicProperties
                         ? h(EnvelopeEditor, { basicProperties: node.basicProperties, onChange })

static/components/ShapeEditor.js

@@ -1,7 +1,8 @@
 import { h } from 'vue';
 
 // Renders a shape's coord table with cascade-shift and an SVG preview.
-// `shape` is mutated in place; `onChange` called after each mutation.
+// `shape` is mutated in place; `onChange` called after each mutation with
+// { undo } so callers can revert if needed.
 
 export const ShapeEditor = {
     props: ['shape', 'onChange'],
@@ -14,27 +15,31 @@ export const ShapeEditor = {
             const delta = num - old;
             coord[field] = num;
 
-            // cascade-shift: if x increased past next coord, shift all following
+            const shifted = [];
             if (field === 'x' && delta > 0) {
                 for (let j = i + 1; j < props.shape.coords.length; j++) {
                     if (props.shape.coords[j].x <= num) {
+                        shifted.push({ j, ox: props.shape.coords[j].x });
                         props.shape.coords[j].x += delta;
                     } else break;
                 }
             }
-            props.onChange?.();
+            props.onChange?.({ undo: () => {
+                coord[field] = old;
+                for (const { j, ox } of shifted) props.shape.coords[j].x = ox;
+            }});
         }
 
         function addCoord() {
             const coords = props.shape.coords;
             const lastX = coords.length ? coords[coords.length - 1].x + 1 : 1;
             coords.push({ x: lastX, y: 0, z: 1, isSharp: false });
-            props.onChange?.();
+            props.onChange?.({ undo: () => coords.pop() });
         }
 
         function removeCoord(i) {
-            props.shape.coords.splice(i, 1);
+            const removed = props.shape.coords.splice(i, 1)[0];
-            props.onChange?.();
+            props.onChange?.({ undo: () => props.shape.coords.splice(i, 0, removed) });
         }
 
         function renderSvg() {
@@ -62,12 +67,7 @@ export const ShapeEditor = {
                 viewBox: `0 0 ${W} ${H}`,
                 preserveAspectRatio: 'none',
             }, [
-                h('polyline', {
+                h('polyline', { points, fill: 'none', stroke: '#2a6aaa', 'stroke-width': '1.5' }),
-                    points,
-                    fill: 'none',
-                    stroke: '#2a6aaa',
-                    'stroke-width': '1.5',
-                }),
                 ...coords.map(c => {
                     const [sx, sy] = toSvg(c);
                     return h('circle', { cx: sx, cy: sy, r: 2.5, fill: '#6aacff' });
@@ -101,7 +101,11 @@ export const ShapeEditor = {
                             })),
                             h('td', null, h('input', {
                                 type: 'checkbox', checked: !!coord.isSharp,
-                                onChange: e => { coord.isSharp = e.target.checked; props.onChange?.(); },
+                                onChange: e => {
+                                    const old = coord.isSharp;
+                                    coord.isSharp = e.target.checked;
+                                    props.onChange?.({ undo: () => { coord.isSharp = old; } });
+                                },
                             })),
                             h('td', null, h('button', { onClick: () => removeCoord(i) }, '✕')),
                         ])

static/components/StatusPoller.js

@@ -1,35 +1,20 @@
-import { h, ref, onMounted, onUnmounted } from 'vue';
+import { h, onMounted, onUnmounted, ref } from 'vue';
 import { fetchStatus } from '../api.js';
 
 export const StatusPoller = {
     props: ['store'],
     setup(props) {
         const timer = ref(null);
-        const eta = ref(null);
-
-        function nextInterval(status) {
-            if (!status) return 2000;
-            const pct = status.progress ?? 0;
-            // At 0–20%: poll at centile-of-ETA intervals
-            if (eta.value && pct > 0 && pct <= 20) {
-                return Math.max(500, (eta.value * 10) | 0);
-            }
-            return 2000;
-        }
 
         async function poll() {
             try {
                 const status = await fetchStatus(props.store.credentials);
-                if (status.eta) eta.value = status.eta;
                 props.store.synthesisStatus = status;
-                if (status.frozen) {
+                if (status.frozen) return;
-                    // done — stop polling
-                    return;
-                }
             } catch (_) {
-                // transient error — keep polling
+                // transient — keep polling
             }
-            timer.value = setTimeout(poll, nextInterval(props.store.synthesisStatus));
+            timer.value = setTimeout(poll, 2000);
         }
 
         onMounted(() => { poll(); });
@@ -39,10 +24,16 @@ export const StatusPoller = {
             const s = props.store.synthesisStatus;
             if (!s) return h('div', { class: 'se-status' }, 'Polling…');
 
-            const pct = s.progress ?? 0;
+            const total = s.notes_in_total ?? 0;
-            const label = s.frozen
+            const done  = s.currently_rendered_notes ?? 0;
-                ? (s.error ? `Error: ${s.error}` : 'Done')
+            const pct   = total > 0 ? Math.min(100, Math.round(done / total * 100)) : 0;
-                : `${s.state ?? 'Running'} ${pct}%`;
+
+            let label;
+            if (s.frozen) {
+                label = s.errors ? `Error: ${s.errors}` : 'Done';
+            } else {
+                label = s.remaining_time ?? `Synthesizing… ${pct}%`;
+            }
 
             return h('div', { class: 'se-status' }, [
                 h('span', null, label),