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>

package.json

@@ -1,7 +1,7 @@
 {
   "name": "siteforge",
   "private": true,
-  "version": "2.0.5",
+  "version": "2.0.6",
   "type": "module",
   "scripts": {
     "dev": "vite",