Whether an effects record holds what no re-index can reproduce: runtime
evidence, or a verification by a trace or a test. Such a record is kept
when its symbol leaves the index; anything else is re-derived from source.
List every stored EffectDecl in the workspace as (symbol_id, decl)
pairs by walking the /asd/v1/effects subtree. Read-only. Used by
overview-style consumers (e.g. asd-serve’s /api/v1/effects/overview)
that need the whole distribution rather than one symbol’s decl — the
per-symbol path stays EffectStore::get_effects.