Follow-up to the salvage of #45035 + #48682. The two PRs touched different
functions (resolve_resume_session_id vs get_compression_tip) but #45035's
descendant walk followed ANY parent_session_id child, so a delegate/subagent
child could hijack the resume target. Apply the same _branched_from /
_delegate_from / source!='tool' exclusion the rest of hermes_state.py uses,
so the resume walk only follows genuine compression continuations.
Also updates the unrealistic delegation test fixture to carry the real
_delegate_from marker, and updates 3 list_sessions_rich test mocks for the
order_by_last_active kwarg #48682 added.
AUTHOR_MAP: map PINKIIILQWQ + ailang323 salvage authors.
6dfb8326f5