d5cca7bb2d
Converts OpenClientDirectory to return ClientDirectoryLockHandle instead of RefPtr<ClientDirectoryLock>, and updates all its callers accordingly. ClientDirectoryLockHandle is a move-only RAII wrapper that ensures the lock is automatically dropped when the handle goes out of scope. This simplifies ownership semantics and aligns with diagnostic assertions that verify proper lock dropping. This patch finalizes the transition for quota clients to use ClientDirectoryLockHandle instead of client directory locks directly. Differential Revision: https://phabricator.services.mozilla.com/D243665