Episode highlights per series: tag by lane, group on Episodes page, move to Finished Book when series ends; v2.9.1

- Highlights get a Series field (Lane A / Lane B / General); legacy highlights count as Lane A
- Episodes page groups highlights under each series' title
- Ending a series (scheduled or manual) moves only that series' highlights onto its Finished Book page; other lane and General stay
- Archived highlights keep working: detail pages, sitemap, scripture index and search include them

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

server/helpers.js

@@ -141,6 +141,7 @@ export function sanitizeFeaturedLinks(value) {
 
       return {
         id: typeof item.id === 'string' && item.id.trim() ? item.id.trim() : randomUUID(),
+        lane: item.lane === 'second' || item.lane === 'general' ? item.lane : 'primary',
         title: typeof item.title === 'string' ? item.title.trim().slice(0, 140) : '',
         episodeNumber: typeof item.episodeNumber === 'string' ? item.episodeNumber.trim().slice(0, 20) : '',
         summary: typeof item.summary === 'string' ? item.summary.trim().slice(0, 600) : '',