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/components/PaneFO.js

@@ -155,7 +155,7 @@ export const PaneFO = {
                         : null,
                 );
             } else if (node.type === 'article') {
-                const markDirty = () => props.store.markDirty();
+                const markDirty = () => { node.isDirty = true; props.store.markDirty(); };
                 const rowStyle = 'display:flex;gap:0.4rem;align-items:center;padding:0.2rem 0';
                 children.push(
                     h('h4', H4, `Article: ${node.name}`),
@@ -180,14 +180,20 @@ export const PaneFO = {
                                     style: 'flex:1;min-width:6em',
                                     onInput: onValInput,
                                 }),
-                                h('button', {
-                                    class: 'se-toggle',
-                                    role: 'switch',
-                                    'aria-checked': String(isOverwrite),
-                                    onClick: flip,
-                                }),
-                                h('span', { class: 'se-toggle-label active', style: 'min-width:4.5em' },
-                                    isOverwrite ? 'overwrite' : 'default'),
+                                h('div', { class: 'form-check form-switch mb-0' }, [
+                                    h('input', {
+                                        class: 'form-check-input mt-0',
+                                        type: 'checkbox',
+                                        role: 'switch',
+                                        id: `prop-scope-${idx}`,
+                                        checked: isOverwrite,
+                                        onChange: flip,
+                                    }),
+                                    h('label', {
+                                        class: 'form-check-label',
+                                        for: `prop-scope-${idx}`,
+                                    }, isOverwrite ? 'overwrite' : 'default'),
+                                ]),
                                 h('button', {
                                     class: 'se-btn-remove',
                                     title: 'Remove property',