pub fn default_registry() -> SpawnerRegistryExpand description
Default registry = Subprocess + RustFn (baseline identity worker pre-baked) + empty Operator factory.
RustFnInProcessSpawnerFactory gets one baseline entry (fn_id = "identity")
baked in via mlua_swarm::worker::baseline::extend_with_baseline. This
is the shared bootstrap / smoke worker SoT across each binary (the server / MCP adapter /
one-shot runner) — it structurally replaces the old per-binary inline echo injection.
Usage: default Task path at server startup. If production needs additional
backends, callers bring in a different registry via
build_router_with(engine, custom_registry). The enhance flow
(= patch-spawner / patch-applier / verifier-router / committer axes) uses
default_registry_with_enhance_flow.
The Operator factory is an empty shell with zero registrations (= sids are
dynamically registered per WS connect; see the operator_ws module).