Why: the product conversation path needs the intent journal and
recovery pairing, but making the transcript the authoritative context
would freeze the assembled system prefix (memory/plans/injections go
stale). JournalOnly keeps the session as journal-only: recovery runs
against it, the context always comes from History, and the recovered
outcomes are injected as a system note. Separately, the one-time
History seed was memory-only and silently lost from the second run on
(authority mode); it is now persisted except in JournalOnly mode.
Evidence: GOWORK=off go vet + go test -count=1 ./... green;
TestJournalOnlyRecoversWithoutTranscriptAuthority (journal gets the
replayed pair exactly once, history never enters the journal, the
recovery note precedes the new user message, seeds stay out);
persistedProjection honors JournalOnly; all pre-existing durable and
harness tests pass unchanged (default semantics untouched).
Impact: new opt-in Config.JournalOnly; default (false) behavior is
byte-identical.
Refs: Agent-System-Documents#43 (N3 plan WP2)
weichen