Store<T> Interface

Generic, async, slot-keyed:

type Store<T> = {
  save:    (slot: Slot, value: T) => Promise<Result<SaveHandle, StoreError>>;
  load:    (slot: Slot) => Promise<Result<T, StoreError>>;
  list:    () => Promise<Result<readonly SaveSlot[], StoreError>>;
  remove:  (slot: Slot) => Promise<Result<void, StoreError>>;
  has:     (slot: Slot) => Promise<boolean>;
  history: (slot: Slot) => AsyncIterable<SaveHandle>;
};

A SaveHandle is the corpus metadata wrapped to carry the slot:

type SaveHandle = {
  slot: Slot;
  version: string;     // corpus version id (deterministic content hash)
  content_hash: string;
  created_at: Date;
  parent: SaveHandle | null;
};

Multiple saves to the same slot append a new corpus version with parents pointing at the previous one. load(slot) returns the most recent version. history(slot) is an async iterator from oldest to newest.

StoreError cases

type StoreError =
  | { kind: "not_found"; slot: Slot }
  | { kind: "invalid_data"; issues: readonly string[] }
  | { kind: "serialisation_failed"; cause: string }
  | { kind: "backend_error"; operation: string; cause: string };