Function embed_runtime_worker_threads 

pub fn embed_runtime_worker_threads(default: usize) -> usize

Worker count for the shared embedding Tokio runtime, from XDG parallelism.embed_runtime_threads (GAP-SG-141 B2).

The runtime used to be built with a hard-coded two workers while the enrich drain fanned out up to sixteen blocking callers onto it. default is the host-derived size computed by the caller; this function only applies the operator override.

A value of 0 is rejected in favour of default: worker_threads(0) panics in Tokio, so a typo in the config file would abort the process.