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>

src/App.tsx

@@ -1314,28 +1314,55 @@ function LandingPage({ content }: { content: SiteContent }) {
             <span className="ornament">✦</span>
           </h2>
           <div className="series-grid">
-            <article className="series-card">
-              <img
-                src={content.seriesImageUrl}
-                alt={content.seriesTitle}
-                className="series-art"
-              />
-              <div className="series-info">
-                <p className="series-label">{content.seriesLabel}</p>
-                <h3>{content.seriesTitle}</h3>
-                <p>{content.seriesDescription}</p>
-                <a
-                  href={content.seriesListenUrl || content.platformSpotifyUrl || '/spotify'}
-                  target="_blank"
-                  rel="noreferrer"
-                  className="btn-primary"
-                >
-                  <SpotifyIcon />
-                  {content.seriesListenBtnLabel || 'Listen to Series'}
-                </a>
-                <Link to="/resources" className="btn-secondary">{content.seriesDownloadsBtnLabel || 'View Resources'}</Link>
-              </div>
-            </article>
+            {[
+              {
+                key: 'primary',
+                imageUrl: content.seriesImageUrl,
+                title: content.seriesTitle,
+                label: content.seriesLabel,
+                description: content.seriesDescription,
+                listenUrl: content.seriesListenUrl,
+                listenBtnLabel: content.seriesListenBtnLabel,
+                studySlug: content.seriesStudySlug,
+              },
+              ...(content.secondSeries?.title?.trim()
+                ? [{
+                    key: 'second',
+                    imageUrl: content.secondSeries.imageUrl,
+                    title: content.secondSeries.title,
+                    label: content.secondSeries.label,
+                    description: content.secondSeries.description,
+                    listenUrl: content.secondSeries.listenUrl,
+                    listenBtnLabel: content.secondSeries.listenBtnLabel,
+                    studySlug: content.secondSeries.studySlug,
+                  }]
+                : []),
+            ].map(series => (
+              <article className="series-card" key={series.key}>
+                <img
+                  src={series.imageUrl}
+                  alt={series.title}
+                  className="series-art"
+                />
+                <div className="series-info">
+                  <p className="series-label">{series.label}</p>
+                  <h3>{series.title}</h3>
+                  <p>{series.description}</p>
+                  <a
+                    href={series.listenUrl || content.platformSpotifyUrl || '/spotify'}
+                    target="_blank"
+                    rel="noreferrer"
+                    className="btn-primary"
+                  >
+                    <SpotifyIcon />
+                    {series.listenBtnLabel || content.seriesListenBtnLabel || 'Listen to Series'}
+                  </a>
+                  {series.studySlug
+                    ? <Link to={`/study/${series.studySlug}`} className="btn-secondary">Study Along</Link>
+                    : <Link to="/resources" className="btn-secondary">{content.seriesDownloadsBtnLabel || 'View Resources'}</Link>}
+                </div>
+              </article>
+            ))}
           </div>
         </div>
       </section>
@@ -1708,6 +1735,11 @@ function FinishedSeriesPage({ content }: { content: SiteContent }) {
                   ⬇ Download Album
                 </a>
               )}
+              {book.studySlug && (
+                <Link to={`/study/${book.studySlug}`} className="finished-series-btn-download">
+                  📖 Study This Book
+                </Link>
+              )}
             </div>
             {book.downloadQrUrl && book.downloadUrl && (
               <div className="finished-series-qr">