Add cross-site improvements across three phases

Phase 1 — Quick wins:
- Image lazy-loading on series/resource cards
- Newsletter signup added to Episodes page (before highlights)
- Per-route meta tags via usePageMeta hook (title, og:title, og:description)
- Breadcrumbs on study index, section, and notes pages
- SVG completion checkmark badges on study section list
- Analytics time-range filter (7d / 30d / 90d) in admin panel

Phase 2 — Medium features:
- Related episodes on archived series detail pages
- Resource library two-tier filter (type + tag chips)
- Global search (Fuse.js) moved below sticky header as full-width bar
- Q&A anonymous upvoting with localStorage dedup + admin pin/unpin
- Study enrollment funnel tracking (firstVisitAt, firstCompletionAt) with funnel chart in analytics

Phase 3 — Larger features:
- Study section comments (auto-approve for enrolled users, admin moderation panel)
- Study completion certificate (canvas render, PNG download, shareable public URL)
- Episode script full-text search (mammoth docx extraction, server-side search, admin upload UI)
- Reflection questions renamed from Discussion Questions; quiz answers can be shared to section discussion
- Public certificate route at /certificate/:token with og meta tags
- Comment moderation panel added to admin under Manage > Study Comments

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

server/routes/study-comments.js

@@ -0,0 +1,122 @@
+import { randomUUID } from 'node:crypto'
+import { requireAdminAuth } from '../auth.js'
+import { requireStudyAuth, normalizeStudySlug, normalizeLessonSectionId, isStudyUserEnrolled } from '../study-helpers.js'
+import { state } from '../state.js'
+import { queueStudyCommentsWrite } from '../data.js'
+import { MAX_STUDY_COMMENTS, MAX_STUDY_COMMENT_LENGTH } from '../config.js'
+
+export function register(app) {
+  // GET public-approved comments for a section (no auth)
+  app.get('/api/study-comments/:studySlug/:sectionId', (req, res) => {
+    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
+    }
+
+    const comments = state.studyComments
+      .filter(c => c.studySlug === studySlug && c.sectionId === sectionId && c.isApproved === true)
+      .sort((a, b) => new Date(a.createdAt) - new Date(b.createdAt))
+      .map(c => ({
+        id: c.id,
+        displayName: c.displayName,
+        text: c.text,
+        createdAt: c.createdAt,
+      }))
+
+    res.json({ comments })
+  })
+
+  // POST — enrolled study users post a comment (auto-approved for enrolled users)
+  app.post('/api/study-comments/:studySlug/:sectionId', requireStudyAuth, (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 leave a comment.' }); return
+    }
+
+    const text = typeof req.body?.text === 'string' ? req.body.text.trim() : ''
+    if (!text || text.length < 2 || text.length > MAX_STUDY_COMMENT_LENGTH) {
+      res.status(400).json({ message: `Comment must be between 2 and ${MAX_STUDY_COMMENT_LENGTH} characters.` }); return
+    }
+
+    // Auto-approve for enrolled users
+    const now = new Date().toISOString()
+    const comment = {
+      id: randomUUID(),
+      studySlug,
+      sectionId,
+      userId: user.id,
+      displayName: user.displayName || user.username,
+      text,
+      createdAt: now,
+      isApproved: true,
+      approvedAt: now,
+    }
+
+    state.studyComments.unshift(comment)
+    if (state.studyComments.length > MAX_STUDY_COMMENTS) {
+      state.studyComments = state.studyComments.slice(0, MAX_STUDY_COMMENTS)
+    }
+    queueStudyCommentsWrite()
+
+    res.status(201).json({
+      ok: true,
+      comment: {
+        id: comment.id,
+        displayName: comment.displayName,
+        text: comment.text,
+        createdAt: comment.createdAt,
+      },
+    })
+  })
+
+  // DELETE — enrolled users can delete their own comment
+  app.delete('/api/study-comments/:commentId', requireStudyAuth, (req, res) => {
+    const user = req.studyUser
+    const { commentId } = req.params
+    const idx = state.studyComments.findIndex(c => c.id === commentId && c.userId === user.id)
+    if (idx === -1) {
+      res.status(404).json({ message: 'Comment not found.' }); return
+    }
+    state.studyComments.splice(idx, 1)
+    queueStudyCommentsWrite()
+    res.json({ ok: true })
+  })
+
+  // Admin: list all comments (optionally filter by studySlug)
+  app.get('/api/admin-study-comments', requireAdminAuth, (req, res) => {
+    const { studySlug, sectionId, approved } = req.query
+    let comments = state.studyComments
+    if (studySlug) comments = comments.filter(c => c.studySlug === studySlug)
+    if (sectionId) comments = comments.filter(c => c.sectionId === sectionId)
+    if (approved === 'true') comments = comments.filter(c => c.isApproved === true)
+    if (approved === 'false') comments = comments.filter(c => c.isApproved !== true)
+    res.json({ comments: comments.slice(0, 500) })
+  })
+
+  // Admin: approve a comment
+  app.post('/api/admin-study-comments/:commentId/approve', requireAdminAuth, (req, res) => {
+    const comment = state.studyComments.find(c => c.id === req.params.commentId)
+    if (!comment) { res.status(404).json({ message: 'Comment not found.' }); return }
+    comment.isApproved = true
+    comment.approvedAt = new Date().toISOString()
+    queueStudyCommentsWrite()
+    res.json({ ok: true, comment })
+  })
+
+  // Admin: delete any comment
+  app.delete('/api/admin-study-comments/:commentId', requireAdminAuth, (req, res) => {
+    const idx = state.studyComments.findIndex(c => c.id === req.params.commentId)
+    if (idx === -1) { res.status(404).json({ message: 'Comment not found.' }); return }
+    state.studyComments.splice(idx, 1)
+    queueStudyCommentsWrite()
+    res.json({ ok: true })
+  })
+}