* feat(checkpoint): production-shaped full/delta benchmark with configurable snapshot frequency
- Group benchmark scripts into per-family folders (checkpoint/, sandbox/)
- Extract shared benchmark infrastructure into checkpoint_bench_common.py
- Add checkpoint_delta_snapshot_frequency config (default 1000, process-frozen);
freeze it in make_lead_agent and DeerFlowClient; key the state-schema
adaptation cache by resolved frequency
- New bench_production.py: per-case child processes run N ainvoke turns through
the real lead-agent graph (scripted deterministic model, real AsyncSqliteSaver),
then measure GET /state + POST /history through the real Gateway route stack
in one event loop (httpx ASGITransport), cold/warm accessor-cache split,
cross-mode digest gates
- New summarize_production.py: delta/full ratios plus decision metrics
(snapshot_write_spike, cache_effect_ms, checkpoint_write_share,
auto-discovered history per-limit ratios)
* fix(checkpoint): address production benchmark review
