Add study account engagement features; v1.2.4

- Pause reminders: remindersPausedUntil field + scheduler skip + account UI with 7/14/30-day presets
- Email digest mode: reminderFrequency field (immediate/weekly) + weekly digest email + scheduler + account UI toggle
- Admin user list improvements: streak, reengagement, frequency, pause, per-study lesson progress
- Admin manual re-engagement: POST endpoint + tier selector button in admin panel
- Study bookmarks: bookmarkedSectionIds in progress file + POST/DELETE endpoints + toggle button in lesson UI
- Study completion certificate email: auto-sent on first certificate issuance
- Content fields for certificate and weekly digest email templates in admin

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server/routes/admin-assets.js

@@ -9,6 +9,7 @@ import {
   readUploadsMetadata,
   writeUploadsMetadata,
   getUserNotesFilePath,
+  loadUserProgress,
   queueStudyUsersWrite,
 } from '../data.js'
 import {
@@ -16,7 +17,9 @@ import {
   getStudyCatalog,
   normalizeStudySlug,
   isEnrollableStudySlug,
+  makeUnsubUrl,
 } from '../study-helpers.js'
+import { sendStudyReengagementEmail } from '../email.js'
 
 export function register(app) {
   app.get('/api/admin-assets', requireAdminAuth, async (_req, res) => {
@@ -117,9 +120,19 @@ export function register(app) {
         noteCount = Object.values(notes).filter(n => typeof n === 'string' && n.trim()).length
       } catch { /* ignore */ }
 
+      let progressByStudy = {}
+      try {
+        const prog = await loadUserProgress(user.id)
+        for (const [slug, data] of Object.entries(prog.byStudy)) {
+          progressByStudy[slug] = { completedLessons: (data.completedSectionIds ?? []).length }
+        }
+      } catch { /* ignore */ }
+
       const enrolledStudies = (user.enrolledStudySlugs ?? []).map(slug => {
         const study = catalog.find(s => s.slug === slug)
-        return study ? { slug, title: study.title } : { slug, title: slug }
+        return study
+          ? { slug, title: study.title, completedLessons: progressByStudy[slug]?.completedLessons ?? 0 }
+          : { slug, title: slug, completedLessons: 0 }
       })
 
       return {
@@ -132,12 +145,50 @@ export function register(app) {
         noteCount,
         subscribeNewsletter: user.subscribeNewsletter !== false,
         studyRemindersEnabled: user.studyRemindersEnabled === true,
+        reminderFrequency: user.reminderFrequency ?? 'immediate',
+        remindersPausedUntil: user.remindersPausedUntil ?? null,
+        currentStreak: user.currentStreak ?? 0,
+        longestStreak: user.longestStreak ?? 0,
+        reengagementSentAt: user.reengagementSentAt ?? {},
       }
     }))
 
     res.json({ users })
   })
 
+  app.post('/api/admin/study-users/:id/send-reengagement', requireAdminAuth, async (req, res) => {
+    const user = state.studyUsers.find(u => u.id === req.params.id)
+    if (!user) { res.status(404).json({ message: 'User not found.' }); return }
+
+    const tier = req.body?.tier
+    if (tier !== 't1' && tier !== 't2' && tier !== 't3') {
+      res.status(400).json({ message: 'tier must be t1, t2, or t3.' }); return
+    }
+
+    const studies = Array.isArray(state.cachedSiteContent?.studies) ? state.cachedSiteContent.studies : []
+    const enrolledStudySlugs = Array.isArray(user.enrolledStudySlugs) ? user.enrolledStudySlugs : []
+    const enrolledStudies = enrolledStudySlugs
+      .map(slug => studies.find(s => normalizeStudySlug(s?.slug) === slug))
+      .filter(Boolean)
+
+    if (enrolledStudies.length === 0) { res.status(400).json({ message: 'User has no enrolled studies.' }); return }
+
+    const firstStudy = enrolledStudies[0]
+    const studyTitle = enrolledStudies.length === 1 ? firstStudy.title : null
+    const canonical = state.cachedSiteContent?.seo?.canonicalUrl || 'https://versebyversewithnate.us/'
+    const base = canonical.endsWith('/') ? canonical.slice(0, -1) : canonical
+    const studyUrl = enrolledStudies.length === 1 ? `${base}/study/${firstStudy.slug}` : `${base}/study`
+    const unsubUrl = makeUnsubUrl(user.id)
+
+    try {
+      await sendStudyReengagementEmail(user.username, user.displayName || user.username, studyTitle, studyUrl, tier, unsubUrl)
+      res.json({ ok: true })
+    } catch (err) {
+      console.error(`[admin] manual reengagement send failed for ${user.username}:`, err)
+      res.status(500).json({ message: 'Failed to send email.' })
+    }
+  })
+
   app.patch('/api/admin/study-users/:id', requireAdminAuth, (req, res) => {
     const user = state.studyUsers.find(u => u.id === req.params.id)
     if (!user) { res.status(404).json({ message: 'User not found.' }); return }

server/routes/study-account.js

@@ -218,6 +218,8 @@ export function register(app) {
         displayName: user.displayName ?? '',
         subscribeNewsletter: user.subscribeNewsletter !== false,
         studyRemindersEnabled: user.studyRemindersEnabled === true,
+        reminderFrequency: user.reminderFrequency ?? 'immediate',
+        remindersPausedUntil: user.remindersPausedUntil ?? null,
         avatarUrl: getStudyAvatarUrl(user),
       },
       stats: {
@@ -303,6 +305,20 @@ export function register(app) {
     const studyRemindersEnabled = req.body?.studyRemindersEnabled === true
     user.subscribeNewsletter = subscribeNewsletter
     user.studyRemindersEnabled = studyRemindersEnabled
+
+    const reminderFrequency = req.body?.reminderFrequency
+    if (reminderFrequency === 'weekly' || reminderFrequency === 'immediate') {
+      user.reminderFrequency = reminderFrequency
+    }
+
+    const rawPaused = req.body?.remindersPausedUntil
+    if (rawPaused === null || rawPaused === '') {
+      user.remindersPausedUntil = null
+    } else if (typeof rawPaused === 'string') {
+      const parsed = new Date(rawPaused)
+      user.remindersPausedUntil = !isNaN(parsed.getTime()) && parsed.getTime() > Date.now() ? parsed.toISOString() : null
+    }
+
     user.updatedAt = new Date().toISOString()
     queueStudyUsersWrite()
 
@@ -310,7 +326,13 @@ export function register(app) {
       syncContactToResend(user.displayName || user.username, user.username).catch(err => console.error('[study-account] resend sync error:', err))
     }
 
-    res.json({ ok: true, subscribeNewsletter: user.subscribeNewsletter, studyRemindersEnabled: user.studyRemindersEnabled === true })
+    res.json({
+      ok: true,
+      subscribeNewsletter: user.subscribeNewsletter,
+      studyRemindersEnabled: user.studyRemindersEnabled === true,
+      reminderFrequency: user.reminderFrequency ?? 'immediate',
+      remindersPausedUntil: user.remindersPausedUntil ?? null,
+    })
   })
 
   app.post('/api/study-account/request-email-change', studyAuthRateLimiter, requireStudyAuth, async (req, res) => {

server/routes/study-certificate.js

@@ -4,6 +4,8 @@ import { requireAdminAuth } from '../auth.js'
 import { requireStudyAuth, normalizeStudySlug, isStudyUserEnrolled, getStudyTitleBySlug } from '../study-helpers.js'
 import { state } from '../state.js'
 import { loadUserProgress, queueStudyCertificatesWrite } from '../data.js'
+import { sendStudyCertificateEmail, getCanonicalBaseUrl } from '../email.js'
+import { buildAbsoluteUrl } from '../helpers.js'
 
 const publicCertRateLimiter = rateLimit({
   windowMs: 15 * 60 * 1000,
@@ -95,6 +97,9 @@ export function register(app) {
       }
       state.studyCertificates.push(cert)
       queueStudyCertificatesWrite()
+      const certUrl = buildAbsoluteUrl(getCanonicalBaseUrl(), `/study/certificate/${cert.token}`)
+      sendStudyCertificateEmail(user.username, user.displayName || user.username, cert.studyTitle, certUrl)
+        .catch(err => console.error('[study-certificate] email exception:', err))
     }
 
     res.json({ ok: true, token: cert.token, issuedAt: cert.issuedAt })

server/routes/study-data.js

@@ -171,6 +171,7 @@ export function register(app) {
 
     const progress = await loadUserProgress(user.id)
     const completedSectionIds = progress.byStudy[studySlug]?.completedSectionIds ?? []
+    const bookmarkedSectionIds = progress.byStudy[studySlug]?.bookmarkedSectionIds ?? []
 
     // Record first visit timestamp on the user record (additive, never overwrite)
     if (!user.firstVisitAt) {
@@ -178,7 +179,7 @@ export function register(app) {
       queueStudyUsersWrite()
     }
 
-    res.json({ studySlug, completedSectionIds })
+    res.json({ studySlug, completedSectionIds, bookmarkedSectionIds })
   })
 
   app.post('/api/study-progress/:studySlug/:sectionId', requireStudyAuth, async (req, res) => {
@@ -301,6 +302,45 @@ export function register(app) {
     res.json({ ok: true, studySlug, sectionId, answers })
   })
 
+  // ── Bookmarks ─────────────────────────────────────────────────────────────
+
+  app.post('/api/study-progress/:studySlug/:sectionId/bookmark', requireStudyAuth, async (req, res) => {
+    const user = req.studyUser
+    const studySlug = normalizeStudySlug(req.params.studySlug)
+    const sectionId = normalizeLessonSectionId(req.params.sectionId)
+    if (!studySlug || !sectionId) { res.status(400).json({ message: 'Invalid study slug or section id.' }); return }
+    if (!isStudyUserEnrolled(user, studySlug)) { res.status(403).json({ message: 'Please enroll in this study to bookmark lessons.' }); return }
+
+    const progress = await loadUserProgress(user.id)
+    const studyProgress = progress.byStudy[studySlug] ?? { completedSectionIds: [], bookmarkedSectionIds: [] }
+    const bookmarkedSectionIds = Array.isArray(studyProgress.bookmarkedSectionIds) ? studyProgress.bookmarkedSectionIds : []
+    if (!bookmarkedSectionIds.includes(sectionId)) {
+      studyProgress.bookmarkedSectionIds = [...bookmarkedSectionIds, sectionId]
+    }
+    progress.byStudy[studySlug] = studyProgress
+    progress.updatedAt = new Date().toISOString()
+    state.studyProgressCache.set(user.id, progress)
+    queueUserProgressWrite(user.id)
+    res.json({ ok: true, studySlug, bookmarkedSectionIds: studyProgress.bookmarkedSectionIds })
+  })
+
+  app.delete('/api/study-progress/:studySlug/:sectionId/bookmark', requireStudyAuth, async (req, res) => {
+    const user = req.studyUser
+    const studySlug = normalizeStudySlug(req.params.studySlug)
+    const sectionId = normalizeLessonSectionId(req.params.sectionId)
+    if (!studySlug || !sectionId) { res.status(400).json({ message: 'Invalid study slug or section id.' }); return }
+    if (!isStudyUserEnrolled(user, studySlug)) { res.status(403).json({ message: 'Not enrolled.' }); return }
+
+    const progress = await loadUserProgress(user.id)
+    const studyProgress = progress.byStudy[studySlug] ?? { completedSectionIds: [], bookmarkedSectionIds: [] }
+    studyProgress.bookmarkedSectionIds = (studyProgress.bookmarkedSectionIds ?? []).filter(id => id !== sectionId)
+    progress.byStudy[studySlug] = studyProgress
+    progress.updatedAt = new Date().toISOString()
+    state.studyProgressCache.set(user.id, progress)
+    queueUserProgressWrite(user.id)
+    res.json({ ok: true, studySlug, bookmarkedSectionIds: studyProgress.bookmarkedSectionIds })
+  })
+
   // ── Community ─────────────────────────────────────────────────────────────
 
   app.get('/api/study-community', requireStudyAuth, async (req, res) => {