Simplify: remove dead code and redundancy across vue app

- Delete ObjectBasic (defined, never imported)
- ObjectShort: remove unused node prop
- exporter: export stressorToString; use in patchBarMeta (removes inline duplicate)
- PaneFO: import stressorToString from exporter; extract H4 style constant,
  shapeSection() helper, instrOnChange() helper; remove apply param from
  makeChangeHandler (was always () => markDirty()); remove unnecessary ?.
  on always-initialized arrays (variations, labelSpecs, subvariations)
- PaneSubObjects: explicit hasChildren on all item kinds; bars at score
  level get hasChildren based on voices; remove stale kind-list fallback
- ast-parser coerce(): remove unreachable s.trim() check ('' handled above)
- PaneCP: fix post-export synthesisStatus reset to use real field names

static/ast-parser.js

@@ -7,7 +7,7 @@ function coerce(s) {
     if (s === 'False' || s === 'N' || s === 'off' || s === 'false') return false;
     if (s === '') return s;
     const n = Number(s);
-    if (!isNaN(n) && s.trim() !== '') return n;
+    if (!isNaN(n)) return n;
     return s;
 }