Replace the raw <textarea> front-matter editor with a CodeMirror 5 instance —
the same editor family the .zddc previewer already uses (and already bundled in
browse, so no added weight). Gains: YAML syntax highlighting, line numbers, and
the shared js-yaml lint gutter; one consistent editing feel across the two YAML
surfaces.
- Mount fmCM (mode:yaml, lineNumbers, lint gutter, readOnly when not writable)
into a host div; refresh on the next frame so it measures correctly.
- Route every front-matter read/write through fmCM.getValue()/setValue() and
the change event (sync-on-open, dirty tracking, the rename cue, Cancel, save).
- The old textarea placeholder (recognised front-matter keys) becomes a greyed
caption under the header whose tooltip carries the full key list — CodeMirror
5 has no built-in placeholder. Arbitrary keys remain free either way.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
ZDDC
cfe379d4f9