Frozen per-slug map of forward-statement horizon days.
Derived once from the registry — recompute the lazy snapshot on each call
so consumers always observe the registry's current state when running
under hot-reload or in tests that swap modules. The result is frozen to
prevent accidental mutation by callers.
Returns Readonly<Record<string,number>>
Frozen Record<slug, horizonDays> mirroring the registry.
Frozen per-slug map of forward-statement horizon days.
Derived once from the registry — recompute the lazy snapshot on each call so consumers always observe the registry's current state when running under hot-reload or in tests that swap modules. The result is frozen to prevent accidental mutation by callers.