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>

src/content.ts

@@ -68,6 +68,9 @@ export interface RedirectRule {
 
 export interface PodcastFeaturedLink {
   id: string
+  // Which series this highlight belongs to: Lane A (primary), Lane B (second), or general.
+  // Missing = primary (older highlights were all about the one running series).
+  lane?: 'primary' | 'second' | 'general'
   title: string
   episodeNumber?: string
   summary: string
@@ -110,6 +113,8 @@ export interface FinishedBook {
   season: number
   // The study that goes with this book, so the card can offer both "Listen" and "Study"
   studySlug?: string
+  // Episode highlights that were featured while this series was playing, kept for its page
+  highlights?: PodcastFeaturedLink[]
   downloadUrl?: string
   downloadQrUrl?: string
 }
@@ -666,3 +671,11 @@ export const DEFAULTS: SiteContent = {
     ],
   },
 }
+
+// Highlights currently featured plus those archived onto finished books (so their detail pages keep working).
+export function getAllHighlights(content: Pick<SiteContent, 'podcastFeaturedLinks' | 'finishedBooks'>): PodcastFeaturedLink[] {
+  return [
+    ...(content.podcastFeaturedLinks ?? []),
+    ...(content.finishedBooks ?? []).flatMap(book => book.highlights ?? []),
+  ]
+}