Article export + Bootstrap toggle + export change log

- patchScore() now accepts articles[] and returns { text, log } instead
  of a plain string. Dirty articles are re-serialized into the articles:
  block (block style, replacing any existing flow-style entries). Clean
  articles bypass the patcher entirely.
- article.isDirty is set on direct property edits so the exporter can
  distinguish directly changed entities from propagated dirty state.
- patchScore() log collects { level:'changed', path } for each patched
  article/instrument/bar, and a { level:'info', message } entry for the
  count of bar documents passed through unchanged.
- CP pane shows the export log above the status poller after each export.
- Article scope toggle replaced with Bootstrap form-check form-switch;
  hand-rolled .se-toggle CSS removed.
- Test suite updated for { text, log } return; 11 new assertions (188 total).

static/exporter.js

@@ -137,8 +137,46 @@ export function exportInstrument(instr) {
     return lines.join('\n');
 }
 
+// ── Articles ───────────────────────────────────────────────────────────────
+// RFC §4.3: articles: MAPPING { LABEL: { ATTR: VALUE ... } ... }
+
+function serializeArticleValue(v) {
+    if (typeof v === 'boolean') return String(v);
+    if (typeof v === 'number') return String(v);
+    const s = String(v);
+    return /[:#\[\]{}&*!,|>'"%@`]/.test(s) ? JSON.stringify(s) : s;
+}
+
+function buildArticlesBlock(articles) {
+    const lines = ['articles:'];
+    for (const art of articles) {
+        const props = (art.properties ?? []).filter(p => p.name);
+        if (!props.length) continue;
+        lines.push(`  ${art.name}:`);
+        for (const p of props) lines.push(`    ${p.name}: ${serializeArticleValue(p.value)}`);
+    }
+    return lines.length > 1 ? lines.join('\n') : null;
+}
+
+function patchArticles(text, articles) {
+    const newBlock = buildArticlesBlock(articles);
+    if (!newBlock) return text;
+    const lines = text.split('\n');
+    const artIdx = lines.findIndex(l => /^articles\s*:/.test(l));
+    if (artIdx !== -1) {
+        let end = artIdx + 1;
+        while (end < lines.length && (lines[end] === '' || lines[end].startsWith(' ') || lines[end].startsWith('\t'))) end++;
+        lines.splice(artIdx, end - artIdx, newBlock);
+    } else {
+        const instrIdx = lines.findIndex(l => /^instrument\s/.test(l));
+        const insertAt = instrIdx !== -1 ? instrIdx : lines.length;
+        lines.splice(insertAt, 0, newBlock, '');
+    }
+    return lines.join('\n');
+}
+
 // ── Score patch ────────────────────────────────────────────────────────────
-// Replace dirty instrument blocks and dirty bar _meta blocks.
+// Replace dirty article, instrument, and bar _meta blocks.
 // Voice note content in bar documents is left verbatim.
 
 const META_KEYS = ['title', 'composer', 'source', 'encrypter'];
@@ -242,24 +280,40 @@ function patchBarMeta(doc, bar) {
     return out.join('\n');
 }
 
-export function patchScore(rawScoreText, instruments, bars = [], info = null) {
+export function patchScore(rawScoreText, instruments, bars = [], info = null, articles = []) {
+    const log = [];
     const SEP = '\n---\n';
     const [header, ...barDocs] = rawScoreText.split(SEP);
 
-    const patchedHeader = patchInstrumentHeader(patchMetadata(header, info), instruments);
+    let patchedHeader = patchMetadata(header, info);
 
-    if (!barDocs.length) return patchedHeader;
+    const dirtyArticles = articles.filter(a => a.isDirty);
+    if (dirtyArticles.length) {
+        patchedHeader = patchArticles(patchedHeader, articles);
+        for (const a of dirtyArticles) log.push({ level: 'changed', path: `articles / ${a.name}` });
+    }
+
+    patchedHeader = patchInstrumentHeader(patchedHeader, instruments);
+    for (const i of instruments.filter(i => i.isDirty)) log.push({ level: 'changed', path: `instrument / ${i.name}` });
+
+    if (!barDocs.length) return { text: patchedHeader, log };
 
     const barMap = {};
     for (const bar of bars) barMap[bar.id] = bar;
 
+    let passedThrough = 0;
     const patchedBarDocs = barDocs.map(doc => {
         const m = doc.match(/^_id:\s*(\S+)/m);
-        if (!m) return doc;
+        if (!m) { passedThrough++; return doc; }
         const bar = barMap[m[1]];
-        if (!bar?.isDirty) return doc;
+        if (!bar?.isDirty) { passedThrough++; return doc; }
+        log.push({ level: 'changed', path: `bar / ${bar.id}` });
         return patchBarMeta(doc, bar);
     });
 
-    return [patchedHeader, ...patchedBarDocs].join(SEP);
+    if (passedThrough > 0) {
+        log.push({ level: 'info', message: `${passedThrough} bar document${passedThrough !== 1 ? 's' : ''} passed through unchanged` });
+    }
+
+    return { text: [patchedHeader, ...patchedBarDocs].join(SEP), log };
 }