actions/action_types.ts

A spec paired with its optional handler — the composable unit passed to register_action_ws and create_rpc_client. The server uses both fields; the client reads only spec (the handler is ignored, harmless). Shared fuz_app primitives (e.g. heartbeat_action) export a complete tuple so consumers spread them into both sides' actions arrays without inventing per-repo ping plumbing.

Polymorphic on kind: request_response specs require a handler for dispatch; remote_notification specs may declare a stub handler for symmetry but are dispatcher-handled (e.g. cancel); local_call specs never reach a network dispatcher. The WS dispatcher only invokes handlers on request_response actions; everything else is registry-only.