Captures the "super FFI" roadmap (future-work.md) and a concrete design for
item #1, typed host callbacks via {.ffiHost.} (design-host-callbacks.md),
including the per-language host-consumption sketches and the non-blocking
FFI-thread contract the generated wrappers must enforce.
The design is grounded in the existing threading model: a host answering from
its own thread cannot complete a chronos Future directly, so the completion
path mirrors the request path in reverse — enqueue + ThreadSignalPtr signal,
drained and completed on the FFI (event-loop) thread.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
