Opaque keyset cursor mirroring messaging_dal::ConversationsSearchCursor. Carries the (last_message_at, id) pair the DAL sorts on; callers echo the cursor verbatim into the next request to walk back through the inbox.

A (resource_kind, resource_id) reference. Closed enum on kind so extending to new resource types is a one-line addition on both this crate and the underlying DAL.

Expandable array type

Opaque keyset cursor mirroring messaging_dal::ConversationsSearchCursor. Carries the (last_message_at, id) pair the DAL sorts on; callers echo the cursor verbatim into the next request to walk back through the inbox.

Active participants for every conversation in conversations, flat and grouped by the client on conversation_id (mirrors the snapshot's flat-array shape). business_name is hydrated here so the inbox can label each row by its counterparty without a per-conversation fetch.