session.resume built two projections of the same lineage with two separate
get_messages_as_conversation calls — the model-fed copy (tip rows, alternation-
repaired) and the display copy (full lineage, verbatim). The display fetch
already reads a superset of the model fetch (the tip rows are part of the
lineage), so the second call re-scanned the same messages.
Add SessionDB.get_resume_conversations(): one lineage SELECT, split into the tip
(model) and full (display) projections in memory via the extracted
_rows_to_conversation helper. Byte-identical to the two separate reads
(test_get_resume_conversations_matches_separate_reads covers a lineage with a
dangling tool-call tail so repair diverges the two lengths, a single session,
and replayed-user dedup). Both session.resume build paths (deferred + eager) now
use it; the subagent single-read path is unchanged.
From the Desktop performance audit (P1: "Remove repeated resume transcript
work") — the gateway half. The renderer's concurrent REST prefetch is left as-is
(the audit flags dropping it as measure-first).
Brooklyn Nicholson
206953fb66