//! Shared low-level support helpers for run-command tests.
//!
//! Responsibilities:
//! - Provide process-state helpers that are awkward to inline in individual suites.
//! - Keep lock- and PID-oriented probes centralized for reuse.
//!
//! Not handled here:
//! - Task fixtures or config builders.
//! - Production lock management logic.
//!
//! Invariants/assumptions:
//! - Helpers remain deterministic enough for local CI.
//! - PID probes stay best-effort and return only confirmed-dead processes.
pub