Redo /newsletter and /nuggets pages; add Nuggets episode tags with admin editor; v2.37.0

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

server.js

@@ -28,6 +28,7 @@ import {
   loadStudySessionsFromDisk,
   queueStudySessionsWrite,
   loadNewsletterIssuesFromDisk,
+  loadNuggetsTagsFromDisk,
   createBackupSnapshot,
   refreshContentCaches,
   queueHitStatsWrite,
@@ -194,6 +195,7 @@ Promise.all([
   loadWebhooksFromDisk(),
   loadStudySessionsFromDisk(),
   loadNewsletterIssuesFromDisk(),
+  loadNuggetsTagsFromDisk(),
   refreshContentCaches(),
 ])
   .catch(err => {