Effect-smol source and workflows

Always treat the checkout’s Effect Smol source as authoritative and inspect nearby source/tests before implementing. Prefer Effect.gen, named Effect.fn/Effect.fnUntraced, pipeable operators, Effect.callback, Effect.void, and DateTime.nowAsDate; Effect v4 beta uses Effect.forkIn(scope), not absent fork/forkDaemon. Use Effect.cached for concurrent in-flight deduplication and Schema decoding over manual Promise/Fiber caches or JSON.parse, because remembered APIs and ad hoc ownership drift.