One companion study guide per series; v2.9.8

- Second series gets its own guide (Resources page card, download page, admin fields)
- When a series ends (scheduled or manual) its guide moves onto its Finished Book, which shows a guide button; the main series' guide is cleared unless the launch supplies a new one
- Lane B launch schedule can supply the incoming series' guide
- Download lookup covers second-series and finished-book guides; guide URLs are sanitized on save and on use

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

server/routes/admin-content.js

@@ -66,11 +66,24 @@ function readCurrentSeries(content, lane) {
     return {
       title: s.title ?? '', description: s.description ?? '', imageUrl: s.imageUrl ?? '',
       season: s.season, studySlug: s.studySlug ?? '',
+      guide: s.guide?.title ? s.guide : undefined,
     }
   }
   return {
     title: content.seriesTitle ?? '', description: content.seriesDescription ?? '', imageUrl: content.seriesImageUrl ?? '',
     season: content.seriesSeason, studySlug: content.seriesStudySlug ?? '',
+    // The main series' guide lives in the flat studyGuide* fields
+    guide: content.studyGuideTitle?.trim()
+      ? {
+          title: content.studyGuideTitle,
+          description: content.studyGuideDescription ?? '',
+          downloadUrl: content.studyGuideDownloadUrl ?? '',
+          amazonUrl: content.studyGuideUrl ?? '',
+          amazonLabel: content.studyGuideAmazonButtonLabel ?? '',
+          appleBooksUrl: content.studyGuideAppleBooksUrl ?? '',
+          appleBooksLabel: content.studyGuideAppleBooksLabel ?? '',
+        }
+      : undefined,
   }
 }
 
@@ -96,6 +109,7 @@ function applySeriesTransition(content, sched, lane = 'primary') {
         imageUrl: current.imageUrl,
         season: current.season ?? ((newSeason ?? 2) - 1 || 1),
         ...(current.studySlug ? { studySlug: current.studySlug } : {}),
+        ...(current.guide ? { guide: current.guide } : {}),
         ...(endingHighlights.length > 0 ? { highlights: endingHighlights.map(({ lane: _lane, ...link }) => link) } : {}),
       }
     : null
@@ -142,6 +156,8 @@ function applySeriesTransition(content, sched, lane = 'primary') {
           description: sched.newDescription?.trim() ?? '',
           imageUrl: sched.newImageUrl?.trim() || content.secondSeries?.imageUrl || '',
           studySlug: newStudySlug,
+          // The ending series' guide moved onto its Finished Book; the incoming series brings its own
+          guide: sched.newGuide?.title?.trim() ? sched.newGuide : undefined,
           ...(newSeason ? { season: newSeason } : {}),
         },
       }
@@ -152,6 +168,13 @@ function applySeriesTransition(content, sched, lane = 'primary') {
         seriesLabel: 'Now Playing',
         seriesStudySlug: newStudySlug,
         ...(newSeason ? { seriesSeason: newSeason } : {}),
+        // The ending series' guide moved onto its Finished Book; unless the launch brings a new one, clear it
+        ...(current.guide && !sched.newStudyGuideTitle?.trim()
+          ? {
+              studyGuideTitle: '', studyGuideDescription: '', studyGuideDownloadUrl: '', studyGuideUrl: '',
+              studyGuideAmazonButtonLabel: '', studyGuideAppleBooksUrl: '', studyGuideAppleBooksLabel: '',
+            }
+          : {}),
       }
 
   const next = sanitizeSiteContent({