CI caught the sibling site the in-place fix missed: legacy (non-in-place)
compression rotates via publish_compression_child, where a mid-summary
append previously stranded in the closed parent. Same watermark + pure-SQL
column clone as archive_and_compact, with session_id rewritten to the child.
Lineage-guard test flipped to pin the appends-flow-freely contract; rotation
watermark tests added (tail follows the child; None = historical behavior).