docs: architecture + comparison — first-round fact pass

[godon-robot]

FIRST ROUND — scoped to the audited pages; api.md not yet verified. Held open for review.

• Worker groups: replica counts column removed entirely rather than refreshed (they had already gone stale once: 5/2 vs actual 10/3). Replica counts are deployment values living in the chart's values.yaml, not architecture. The timeout column stays qualitative — "none by design" on breeder workers (crash recovery via the Optuna DB) is the architectural fact; "2 minutes" was also a chart value.
• Cooperation scaling: the unsourced "diminishing returns after ~10 cooperating breeders" claim is dropped — nothing in engine or notes backs it.
• Causal endpoints: completed to the verified route list from godon-causal main.rs — adds /predict/multihop, /graph, /artifact (the exportable measured map), /walk-view/{sender}, /impact/{breeder_id}, /causes/{breeder_id}.
• Comparison: effectuation claims trimmed to shipped reality (SSH, HTTP — the "APIs" rode on the unshipped Kubernetes effectuator); the Optuna reconnaissance row gains HTTP (Prometheus, HTTP — both shipped).