Function serve_blocking 

pub fn serve_blocking(
    record: FrontDoorRecord,
    bind_addr: &str,
) -> Result<(), String>

Serve the QDP profile for record on bind_addr (e.g. "[fd00::1]:80" on the mesh, or "127.0.0.1:8080" locally). Blocks the calling thread on the accept loop — the caller is expected to run this on a dedicated thread.

Native-only (tiny_http). Every request is dispatched through the pure route, so the network path and the tested path share one implementation.