Loads a checkpoint by ID. Returns undefined if not found.
Loads the latest checkpoint for a given execution ID.
Lists all checkpoint summaries for a given execution ID.
Deletes a checkpoint by ID. Returns true if found and deleted.
Deletes all checkpoints for a given execution ID.
Returns total number of checkpoints across all executions.
Clears all checkpoints.
In-memory checkpoint store with bounded storage. Checkpoints are evicted on a per-execution basis (oldest first) when limits are exceeded.