feat: add empty address cleanup feature (#765)

* feat: add empty address cleanup feature

Add functionality to clean up email addresses that have never received any emails and were created more than N days ago.

Changes:
- Add emptyAddress cleanup type to backend cleanup logic
- Add enableEmptyAddressAutoCleanup and cleanEmptyAddressDays to CleanupSettings model
- Add scheduled task support for auto-cleanup of empty addresses
- Add UI controls in Maintenance page for manual and auto cleanup
- Add i18n support (English and Chinese translations)

🤖 Generated with [Claude Code](https://claude.ai/code)

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

* chore: update dependencies

Update package.json and lock files across frontend, worker, pages, and vitepress-docs

🤖 Generated with [Claude Code](https://claude.ai/code)

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

* docs: update CHANGELOG for empty address cleanup feature

Add entry for new maintenance page feature to clean up email addresses with no emails older than N days

🤖 Generated with [Claude Code](https://claude.ai/code)

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

---------

Co-authored-by: Claude <noreply@anthropic.com>

vitepress-docs/package.json

@@ -4,9 +4,9 @@
   "version": "1.1.0",
   "type": "module",
   "devDependencies": {
-    "@types/node": "^24.10.0",
+    "@types/node": "^24.10.1",
     "vitepress": "^1.6.4",
-    "wrangler": "^4.46.0"
+    "wrangler": "^4.47.0"
   },
   "scripts": {
     "dev": "vitepress dev docs",