feat(api): Human Input Node (backend part) (#31646)

The backend part of the human in the loop (HITL) feature and relevant architecture / workflow engine changes.

Signed-off-by: yihong0618 <[email protected]>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: -LAN- <[email protected]>
Co-authored-by: 盐粒 Yanli <[email protected]>
Co-authored-by: CrabSAMA <[email protected]>
Co-authored-by: Stephen Zhou <[email protected]>
Co-authored-by: Copilot <[email protected]>
Co-authored-by: yihong <[email protected]>
Co-authored-by: Joel <[email protected]>