Development record

The implement loop's pickGit (pick commit, sync merge) runs with ScrubbedEnv, so it lacks gc.auto=0, maintenance.auto=false and GIT_NO_LAZY_FETCH: a pick commit can trigger gc --auto (and gc.recentObjectsHook on git 2.42+), and a merge in a partial clone can lazy-fetch through a promisor transport. Found by the security-drain-2026-10-09 lane W sweep; kept uncommitted until its fix lands.