cea25ef465
When syncing highlights between Readest and KOReader, the `note` field was forced to an empty string (`""`) for annotations and bookmarks without notes. KOReader's native annotations omit the field entirely when no note exists, so the empty string caused KOReader to treat every synced highlight as having a (blank) note. Apply the same omission in both push and pull directions. Co-authored-by: Claude <noreply@anthropic.com>