* fix(cron): skip isError payloads when picking summary/delivery content
buildEmbeddedRunPayloads appends isError warnings as the last payload.
Three functions in helpers.ts iterate last-to-first and pick the error
over real agent output. Use two-pass selection: prefer non-error payloads,
fall back to error-only when no real content exists.
Fixes: pickSummaryFromPayloads, pickLastNonEmptyTextFromPayloads,
pickLastDeliverablePayload — all now accept and filter isError.
* Changelog: note cron payload isError filtering (#21454)
---------
Co-authored-by: Tak Hoffman <[email protected]>
