Add a new interface to compact rocksdb manually

we cannot trigger rocksdb compaction manually now. it need to add a new interface to do this

Look for existing RocksDB integration in the codebase, likely in storage or engine modules. Identify where compaction is currently triggered and add a new public API method. Check for tests related to storage operations to understand the testing pattern. Ensure the interface is thread-safe and properly documented.

Written by the indexing model from the issue text.