OptionaldocumentsAlready-parsed canonical documents (e.g. from loadStackFile).
OptionalenvEnv record for ${VAR} substitution when yaml is given (default {}).
OptionalorganizationInjected into documents missing metadata.organization before validation.
OptionalyamlRaw multi-document stack YAML, parsed with parseStackDocuments.
Stack source: pre-parsed documents, or raw YAML + substitution env.