- Core returns `InboundResult` — a typed struct with an optional
`NewConversation` and a `FrameOutcome` of decrypted messages.
- Client surfaces app-facing events via `Vec<Event>`, translated from
`InboundResult` at the boundary.
- MLS group welcomes now produce a `ConversationStarted` event with no
initial content, fixing the silent-group-join case where the inbox
layer dropped the observation.
- C FFI exposes an `EventList` opaque type with indexed accessors and
an `Invalid` sentinel for OOB / non-applicable reads.
- Symmetric `Inbox` / `InboxV2` handlers: both return
`Result<InboundResult, _>` and own the persistence + ephemeral-key
cleanup for the conversations they create.
- Updated and simplified `docs/adr/0001-client-event-system.md`.
Implement a `client` crate that wraps the `libchat` context behind a
simple `ChatClient<D>` API. The delivery strategy is pluggable via a
`DeliveryService` trait, with two implementations provided:
- `InProcessDelivery` — shared `MessageBus` for single-process tests
- `CDelivery` — C function-pointer callback for the FFI layer
Add a `client-ffi` crate that exposes the client as a C API via
`safer-ffi`. A `generate-headers` binary produces the companion C
header.
Include two runnable examples:
- `examples/in-process` — Alice/Bob exchange using in-process delivery
- `examples/c-ffi` — same exchange written entirely in C; smoketested
under valgrind (to catch memory leaks) in CI
iterates: #71
