Provenance step recorded by each stage

Slots

stage: stage name, e.g. "decompose"
contract: contract class name, e.g. "Decomposer"
implementation: registered implementation name
pkg_version: package version at time of run
params: parameter list used
input_hashes: named character vector of digest::digest hashes
rng_seed: integer RNG state captured before stage ran
timestamp: POSIXct legacy compatibility field; always NA in deterministic provenance
status: "success" or "failure"