Why: N2 is closed; per the completion doc's dependency order N3 is
next and needs a plan grounded in current code (the crash window
between persist and intent commit is unprotected, the product
conversation path has zero durability, span names/attributes do not
follow the GenAI convention, the memory port does not exist).
Evidence: five-area survey with file:line citations at the pinned
baselines (agent-native 74aa60b, backend 7980a8a, core 0b5c774);
audit N1/N21 verified fixed, N6/N20 verified still open.
Impact: documentation only; work starts after this plan merges.
Refs: 2026-10-02-agent-stack-completion.md N3 section
weichen