Reconcile the gateway pending-mirror in _session_attention_summary()
before counting sidebar approval attention, so a parent session's red
approval dot clears once the underlying gateway approval has drained.
Live approvals stay visible; clarify fallback unchanged. WebUI read-path
mitigation; child-session context-propagation root cause stays in #6100.
Co-authored-by: nesquena-hermes <agent@nesquena-hermes>
Co-authored-by: rodboev <rodboev@users.noreply.github.com>