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/study-helpers.js

@@ -74,6 +74,17 @@ export function hashEmailVerifyToken(token) {
 
 // ── Catalog / enrollment helpers ───────────────────────────────────────────
 
+// A study is 'complete' when an admin marks it so, or when it has lessons and every
+// one of them has already been released. Planned studies never auto-complete.
+export function getEffectiveStudyStatus(study) {
+  if (!study || typeof study !== 'object') return 'active'
+  if (study.status === 'planned') return 'planned'
+  if (study.status === 'complete') return 'complete'
+  const sections = Array.isArray(study.sections) ? study.sections : []
+  if (sections.length > 0 && sections.every(isSectionReleased)) return 'complete'
+  return 'active'
+}
+
 export function getStudyCatalog() {
   const fallback = [
     { slug: 'colossians', title: 'Colossians: Rooted in Christ', status: 'active' },
@@ -91,7 +102,7 @@ export function getStudyCatalog() {
       out.push({
         slug,
         title: typeof study?.title === 'string' && study.title.trim() ? study.title.trim() : slug,
-        status: study?.status === 'planned' ? 'planned' : 'active',
+        status: getEffectiveStudyStatus(study),
       })
     }
     if (out.length > 0) return out
@@ -743,9 +754,13 @@ export async function scheduleWeeklyDigestEmails(sendStudyWeeklyDigestEmail) {
         : undefined
       if (!study) continue
 
+      // Finished studies are self-paced: only mention lessons from the last week so a
+      // late enrollee isn't sent the whole back catalogue in one digest.
+      const isComplete = getEffectiveStudyStatus(study) === 'complete'
       for (const section of study.sections ?? []) {
         const releaseTime = getSectionReleaseTime(section)
         if (!Number.isFinite(releaseTime) || releaseTime > nowMs) continue
+        if (isComplete && nowMs - releaseTime > ONE_WEEK_MS) continue
         const sentForStudy = Array.isArray(userSent[studySlug]) ? userSent[studySlug] : []
         if (sentForStudy.includes(section.id)) continue