Follow-up hardening on top of the salvaged #66637 commits:
- _insert_real_user_anchor could place the restored human turn directly
next to user-role scaffolding (index-0 insert before a leading synthetic
user turn, or a scaffolding-only transcript), breaking the strict
alternation contract (#55677). Restoration now merges into trailing
scaffolding (anchor text leads, synthetic flags cleared) and appends
after a user-role compaction summary instead of inserting adjacent.
- _is_real_user_message now also rejects user-role compaction summaries
(the compressor pins the summary to role=user when the tail opens with
an assistant turn), so a summary can no longer satisfy the human-anchor
check and skip restoration.
- _latest_user_task_snapshot reuses the same real-user predicate, so the
deterministic task snapshot can no longer anchor on todo snapshots,
truncation notices, or background-process reports.
- The Historical Task Snapshot rewrite keeps the section terminated with
a blank line; the previous replacement consumed the boundary newlines,
gluing the next '## ' heading mid-line and deleting all later sections
on the next iterative compaction.
- Drop _length_continuation_synthetic (no producer anywhere).
- AUTHOR_MAP entry for enzo-adami.
c03c247e7c