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/routes/admin-content.js

@@ -82,6 +82,12 @@ function applySeriesTransition(content, sched, lane = 'primary') {
   const newSeason = Number.isInteger(sched.newSeason) ? sched.newSeason : undefined
   const newStudySlug = typeof sched.newStudySlug === 'string' ? sched.newStudySlug.trim().toLowerCase() : ''
 
+  // Highlights for the ending series move onto its Finished Book; the other lane's and general ones stay.
+  const allHighlights = Array.isArray(content.podcastFeaturedLinks) ? content.podcastFeaturedLinks : []
+  const isThisLane = link => (link.lane === 'second' ? 'second' : link.lane === 'general' ? 'general' : 'primary') === lane
+  const endingHighlights = current.title.trim() ? allHighlights.filter(isThisLane) : []
+  const keptHighlights = current.title.trim() ? allHighlights.filter(link => !isThisLane(link)) : allHighlights
+
   const archivedBook = current.title.trim()
     ? {
         id: Date.now().toString(36),
@@ -90,6 +96,7 @@ function applySeriesTransition(content, sched, lane = 'primary') {
         imageUrl: current.imageUrl,
         season: current.season ?? ((newSeason ?? 2) - 1 || 1),
         ...(current.studySlug ? { studySlug: current.studySlug } : {}),
+        ...(endingHighlights.length > 0 ? { highlights: endingHighlights.map(({ lane: _lane, ...link }) => link) } : {}),
       }
     : null
 
@@ -126,10 +133,6 @@ function applySeriesTransition(content, sched, lane = 'primary') {
     return study
   })
 
-  const hasOtherLane = lane === 'second'
-    ? Boolean(content.seriesTitle?.trim())
-    : Boolean(content.secondSeries?.title?.trim())
-
   const lanePatch = lane === 'second'
     ? {
         secondSeries: {
@@ -155,8 +158,7 @@ function applySeriesTransition(content, sched, lane = 'primary') {
     ...content,
     ...lanePatch,
     studies,
-    // Highlights belong to whatever is playing now; don't wipe them while the other lane is still running.
-    podcastFeaturedLinks: hasOtherLane ? content.podcastFeaturedLinks : [],
+    podcastFeaturedLinks: keptHighlights,
     finishedBooks: [...(Array.isArray(content.finishedBooks) ? content.finishedBooks : []), ...(archivedBook ? [archivedBook] : [])],
     ...patch,
   })