- Implement thread-safe local config caching with a 5s TTL check.
- Reuse backend client singletons in storage.Active and storage.ForDriver.
- Reset in-memory config cache on configuration saves and updates.
- Create internal/httppool package to manage shared HTTP transports.
- Configure WebDAV client and CDN retrieval to reuse the shared pool.
- Add unit tests for httppool and storage caching behaviors.