KnownResolvedIds

Resolved-ids the library itself references by value. Recognizers (which live in the consuming app) produce these when they detect the corresponding failure, and the library reads them — e.g. the retry executor emits a tailored WARN addendum when an exhausted retry carries GEN_AI_AGENT_SPAN_CLEANUP. Keeping them here, next to the failure taxonomy, keeps the WARN and the recognizer in sync.