--- Base Node --- BaseNode defines the interface for all nodes in a workflow.

--- Batch Flow --- BatchFlow runs the entire flow sequence for each parameter set generated by PrepBatch.

--- Batch Node (Processes items individually) --- BatchNode implements BaseNode to process slices of items.

--- Flow --- Flow orchestrates the execution of connected nodes.

--- Standard Node (with Retry) --- Node implements BaseNode with retry logic.

PocketFlowError represents an error originating from the PocketFlow library.

--- Common Node Implementation Details ---