An out-of-band zero-step turn (durable command lifecycle on an idle log)
advances the log's turn numbering behind ReactLoopAgent's cached lastTurn,
so the next real turn reused a stale number and tripped the session
invariant (turn/start expected N, got 1) — hanging the TUI after any idle
slash command. The log is the numbering authority: take max(cached, logged)
+ 1 at open. The command-goal stub's inject helper also gains the one-shot
injection turn wrap the real agent performs, restoring turn enclosure in
its log assertions.