#2704 gatorwalk-factory: a parsed lifecycle cannot be parsed again (payload schemas keep a validator mark)

Found while working on swamp-club #2667. parseLifecycle lints each payload schema by compiling it with @cfworker/json-schema, whose dereference adds a non-enumerable absolute_uri property to the schema object it is given. The parsed lifecycle keeps that property on its payload schemas, and zod's record parsing copies non-enumerable own keys, so calling parseLifecycle on an already-parsed lifecycle fails with: stages.0.evidence.0.schema.absolute_uri: unknown JSON Schema keyword 'absolute_uri'. Repro: parse any lifecycle with an evidence schema, then parse result.value again. Today's callers seem to avoid it (eject passes jsonSafe(composed); work items parse stored JSON), so it is latent. Fix idea: lint on a structuredClone of the schema, as #2667 does for match fragments.