Retry and cache policies configurable on graph nodes.
Use with StateGraph.addNode for per-node overrides, or with
StateGraph.setNodeDefaults for graph-wide defaults applied at
compile() time. Per-node values always take precedence over defaults.
setNodeDefaults may be called before or after addNode, including as the
last step before compile().
Optional retry policy for handling failures in node execution
The value (ms) of the timeout that fired (runTimeout or idleTimeout).