Add upload email notifications with Seafile direct-upload watcher; v2.0.6

- Portal uploads send one email immediately (host, episode, passage,
  description, filenames) via Resend to NUGGETS_NOTIFY_EMAIL
- Seafile watcher polls /Episode Upload every 15 min for direct uploads
  and sends a notification for any new file not already seen via portal
- Files uploaded through the portal are marked seen so the watcher
  never sends a duplicate notification
- Credentials kept out of git: SEAFILE_TOKEN, SEAFILE_NUGGETS_REPO_ID,
  NUGGETS_NOTIFY_EMAIL now sourced from docker .env file

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

server.js

@@ -64,6 +64,7 @@ import { register as registerDownloads } from './server/routes/downloads.js'
 import { register as registerEpisodes } from './server/routes/episodes.js'
 import { register as registerNuggets } from './server/routes/nuggets.js'
 import { register as registerNuggetsHostUpload } from './server/routes/nuggets-host-upload.js'
+import { startNuggetsSeafileWatcher } from './server/nuggets-seafile-watcher.js'
 import { register as registerFeed } from './server/routes/feed.js'
 import { register as registerQrCodes } from './server/routes/qr-codes.js'
 import { register as registerBiblePassage } from './server/routes/bible-passage.js'
@@ -174,6 +175,7 @@ Promise.all([
     }, BACKUP_INTERVAL_MS)
 
     startReminderScheduler()
+    startNuggetsSeafileWatcher()
 
     // Purge expired study sessions every hour
     setInterval(() => {