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>

frontend/package.json

@@ -49,7 +49,7 @@
     "vite-plugin-wasm": "^3.5.0",
     "workbox-build": "^7.3.0",
     "workbox-window": "^7.3.0",
-    "wrangler": "^4.46.0"
+    "wrangler": "^4.47.0"
   },
   "packageManager": "pnpm@10.10.0+sha512.d615db246fe70f25dcfea6d8d73dee782ce23e2245e3c4f6f888249fb568149318637dca73c2c5c8ef2a4ca0d5657fb9567188bfab47f566d1ee6ce987815c39"
 }