Two concurrent series lanes, Complete studies, self-paced finished books; v2.9.0

- Study status 'complete' (manual or auto when all lessons released); stays enrollable and self-paced (no sequential lock, Resume button, Finished Studies hub section)
- Studies get lane (A/B) and expected start date; planned studies show "Starts <date>"; hub shows next lesson date instead of hardcoded pace
- Second concurrent series (homepage card, admin panel) with its own scheduled launch; transitions are per lane and flip the ending study to Complete and the incoming study to Active
- Finished books link to their study: "Study This Book" on playlist page, audio-only link from hub (playlist stays public, no account)
- Admin: bulk release scheduler (every N days), same-day collision warning, linked-study selects
- Weekly digest no longer dumps a finished study's backlog on late enrollees
- CI: build and tag the container as :beta on pushes to the beta branch

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

server/helpers.js

@@ -290,6 +290,28 @@ function sanitizeColossiansStudySections(value) {
     .filter(item => item.title || item.summary || item.commentary || item.greekNotes.length > 0 || item.studyQuestions.length > 0 || item.passageText || item.checkpointPrompt || item.checkpointQuestions.length > 0)
 }
 
+function sanitizeIsoDate(value) {
+  if (typeof value !== 'string' || !value.trim()) return ''
+  const time = Date.parse(value)
+  return Number.isFinite(time) ? new Date(time).toISOString() : ''
+}
+
+function sanitizeSecondSeries(value) {
+  if (!value || typeof value !== 'object' || Array.isArray(value)) return undefined
+  const str = (v, max) => (typeof v === 'string' ? v.trim().slice(0, max) : '')
+  const season = Number.isInteger(value.season) && value.season >= 1 && value.season <= 999 ? value.season : undefined
+  return {
+    label: str(value.label, 80) || 'Now Playing',
+    title: str(value.title, 160),
+    description: str(value.description, 800),
+    imageUrl: str(value.imageUrl, 500),
+    listenUrl: str(value.listenUrl, 500),
+    listenBtnLabel: str(value.listenBtnLabel, 80),
+    studySlug: str(value.studySlug, 120).toLowerCase().replace(/[^a-z0-9-]/g, '-'),
+    ...(season ? { season } : {}),
+  }
+}
+
 function sanitizeStudies(value) {
   const source = Array.isArray(value) ? value : []
   return source
@@ -303,7 +325,9 @@ function sanitizeStudies(value) {
       showOnHomepage: item.showOnHomepage === true,
       showNewTag: item.showNewTag === true,
       newTagLabel: typeof item.newTagLabel === 'string' ? item.newTagLabel.trim().slice(0, 24) : '',
-      status: item.status === 'planned' ? 'planned' : 'active',
+      status: item.status === 'planned' ? 'planned' : (item.status === 'complete' ? 'complete' : 'active'),
+      lane: item.lane === 'A' || item.lane === 'B' ? item.lane : '',
+      startsAt: sanitizeIsoDate(item.startsAt),
       difficulty: item.difficulty === 'advanced' ? 'advanced' : (item.difficulty === 'intermediate' ? 'intermediate' : 'beginner'),
       estimatedHours: Number.isFinite(Number(item.estimatedHours)) ? Math.max(1, Math.min(500, Number(item.estimatedHours))) : 8,
       completionBadge: typeof item.completionBadge === 'string' ? item.completionBadge.trim().slice(0, 120) : '',
@@ -384,6 +408,7 @@ export function sanitizeSiteContent(siteContent) {
     customBlocks: sanitizeCustomBlocks(siteContent.customBlocks),
     archivedSeries: sanitizeArchivedSeries(siteContent.archivedSeries),
     studies: sanitizeStudies(siteContent.studies),
+    secondSeries: sanitizeSecondSeries(siteContent.secondSeries),
     colossiansStudySections: sanitizeColossiansStudySections(siteContent.colossiansStudySections),
     redirects: sanitizeRedirectRules(siteContent.redirects),
     podcastFeaturedLinks: sanitizeFeaturedLinks(siteContent.podcastFeaturedLinks ?? DEFAULT_PODCAST_FEATURED_LINKS),