Fix VOLUMES/TIMBRE/FM placement: variation properties, not instrument-level

Per RFC §3.2.1.3, VOLUMES, TIMBRE and FM are variation properties. The
previous exporter incorrectly appended them to the first ATTR variation;
they now go into a synthetic root variation (no ATTR) as required.
variationLines() handles these fields directly.

Fix test-parser.mjs fixture paths for standalone execution from repo root.

static/exporter.js

@@ -62,6 +62,7 @@ function labelSpecLines(ls) {
 
 // ── Variation ─────────────────────────────────────────────────────────────
 // Returns YAML lines for one variation MAPPING (no leading "- ").
+// RFC §3.2.1.3: VOLUMES, TIMBRE are variation properties, not instrument-level.
 
 function variationLines(v) {
     const lines = [];
@@ -70,25 +71,34 @@ function variationLines(v) {
     for (const ls of (v.labelSpecs ?? [])) lines.push(...labelSpecLines(ls));
     if (v.spread?.length) lines.push(`SPREAD: [${v.spread.join(', ')}]`);
     if (v.railsbackCurve) { const rc = serializeShape(v.railsbackCurve); if (rc) lines.push(`RAILSBACK_CURVE: "${rc}"`); }
+    const vol = serializeShape(v.volumes);
+    if (vol) lines.push(`VOLUMES: "${vol}"`);
+    const timbre = serializeShape(v.timbre);
+    if (timbre) lines.push(`TIMBRE: "${timbre}"`);
+    for (const fm of (v.fmModulations ?? [])) lines.push(`FM: "${serializeFm(fm)}"`);
     for (const sv of (v.subvariations ?? [])) lines.push(...variationLines(sv));
     return lines;
 }
 
 // ── Instrument character block ─────────────────────────────────────────────
-// VOLUMES / TIMBRE / FM appear at depth 01 (direct instrument children per RFC §3.2.1.3).
+// VOLUMES, TIMBRE, FM are variation properties (RFC §3.2.1.3). The AST parser
-// RAILSBACK_CURVE is depth 02 (inside variation) and is emitted by variationLines().
+// stores them on the instrument because they appear at depth 01 (root variation
+// is implicit when no character: wrapper exists). Promote them into a synthetic
+// root variation here so the export structure is RFC-correct.
 
 function instrCharacterLines(instr) {
-    const extraLines = [];
-    const vol = serializeShape(instr.volumes);
-    if (vol) extraLines.push(`VOLUMES: "${vol}"`);
-    const timbre = serializeShape(instr.timbre);
-    if (timbre) extraLines.push(`TIMBRE: "${timbre}"`);
-    for (const fm of (instr.fmModulations ?? [])) extraLines.push(`FM: "${serializeFm(fm)}"`);
-
     const variations = instr.variations ?? [];
-    const syntheticRoot = instr.basicProperties
+    const hasRootProps = instr.basicProperties || instr.volumes || instr.timbre ||
-        ? { basicProperties: instr.basicProperties, labelSpecs: [], subvariations: [], spread: null, dependsOn: null }
+                         (instr.fmModulations ?? []).length > 0;
+    const syntheticRoot = hasRootProps
+        ? {
+            basicProperties: instr.basicProperties,
+            labelSpecs: [], subvariations: [], spread: null,
+            dependsOn: null, railsbackCurve: null,
+            volumes: instr.volumes,
+            timbre: instr.timbre,
+            fmModulations: instr.fmModulations ?? [],
+          }
         : null;
 
     const allVariations = [
@@ -97,21 +107,17 @@ function instrCharacterLines(instr) {
     ];
 
     if (allVariations.length <= 1) {
-        // Single variation — emit as MAPPING directly under character:
+        const vLines = allVariations.length ? variationLines(allVariations[0]) : [];
-        const vLines = allVariations.length
-            ? [...variationLines(allVariations[0]), ...extraLines]
-            : extraLines;
         return vLines.map(l => `    ${l}`);
     }
 
     // Multiple variations — RFC MAYBE_LIST<VARIATION> as YAML sequence.
     const result = [];
-    for (let i = 0; i < allVariations.length; i++) {
+    for (const v of allVariations) {
-        const vLines = variationLines(allVariations[i]);
+        const vLines = variationLines(v);
-        const allLines = i === 0 ? [...vLines, ...extraLines] : vLines;
+        if (!vLines.length) continue;
-        if (!allLines.length) continue;
+        result.push(`    - ${vLines[0]}`);
-        result.push(`    - ${allLines[0]}`);
+        for (const l of vLines.slice(1)) result.push(`      ${l}`);
-        for (const l of allLines.slice(1)) result.push(`      ${l}`);
     }
     return result;
 }

test-parser.mjs

@@ -1,15 +1,12 @@
 #!/usr/bin/env node
 // Fixture-based compliance test for ast-parser.js + exporter.js
-// Run: node score_editors/vue3_neusik/test-parser.mjs
+// Run: node test-parser.mjs
 
 import { readFileSync } from 'fs';
 import { parseAstLog, buildModel } from './static/ast-parser.js';
 import { exportInstrument, patchScore } from './static/exporter.js';
 
-const FIXTURE = new URL(
+const FIXTURE = new URL('./fixtures/ast.log', import.meta.url);
-    '../../PLAN/vue3js-app-proposal-for-sdk-claude/fixtures/ast.log',
-    import.meta.url
-);
 const text = readFileSync(FIXTURE, 'utf8');
 
 let pass = 0, fail = 0;
@@ -191,10 +188,7 @@ if (alpha) {
 
 // ── patchScore ─────────────────────────────────────────────────────────────
 section('patchScore');
-const SCORE_FIXTURE = new URL(
+const SCORE_FIXTURE = new URL('./fixtures/pathetique.spls', import.meta.url);
-    '../../PLAN/vue3js-app-proposal-for-sdk-claude/fixtures/pathetique.spls',
-    import.meta.url
-);
 const rawScore = readFileSync(SCORE_FIXTURE, 'utf8');
 
 // pathetique.spls contains alpha and ki; dev/piano is a linked instrument not embedded.