PartitionedCache currently takes keys by const& and forwards them into the underlying LRU cache, which also accepts keys by const&. As a result, inserting an rvalue key still forces a copy when the key is stored in the cache.

This is mostly an API/implementation mismatch: the cache must own a key internally, but it should be able to move that key into storage when the caller provides an rvalue.

Proposed improvement:

• Add rvalue overloads for PartitionedCache::put() and the underlying LRU add() path
• Use the key by reference for partition selection / duplicate lookup before moving it
• Move the key into the owned list/node storage at the final insertion point

This would preserve current behavior for lvalue callers while avoiding an unnecessary key copy for rvalue callers.