Status: IN
Forward-only design is both the architecture's most universally applied pattern (spanning event streams, task pipelines, and notification delivery as a single processing primitive) and its primary correctness mechanism (containing temporal gaps, preventing regression, enabling safe cost shifting despite accepted weaknesses) — making it the single most load-bearing architectural constraint across all 25 modules.
Forward-only is universal in scope AND primary in correctness role — uniquely load-bearing
Depends on (SL): forward-only-is-universal-processing-primitive, forward-only-preserves-correctness-despite-accepted-gaps