Suggestion
Open carrier for an LLM- or extractor-emitted hint that something should be persisted. Concrete subtypes decide what — entities (com.embabel.dice.common.SuggestedEntity), propositions (SuggestedProposition), or app-domain facts shipped by downstream modules (e.g. SuggestedBiller).
Implements Derivation so every suggestion carries the same epistemic shape as the things it eventually turns into (Proposition, com.embabel.dice.projection.Projection).
Open by design. DICE owns the two base subtypes and ships the default handlers; downstream modules add new subtypes and register their own SuggestionHandlers. The drainer dispatches by concrete class — unknown subtypes warn-and-drop so a pack shipping a suggestion type the host doesn't know about can't crash the pipeline.