feat(HITL): Emit UserConfirmResultEvent when resuming permission HITL (#2511)

## Summary

- Emit `UserConfirmResultEvent` when `ReActAgent` accepts
`ConfirmResult` payloads while resuming permission HITL.
- Persist the pending confirmation request `replyId` on the live
assistant message so the result event can correlate with the earlier
`RequireUserConfirmEvent`.
- Validate that resume `ConfirmResult`s fully cover all current `ASKING`
tool calls before emitting the event or mutating context.
- Update HITL tests and event docs for the new resume-event behavior.