//! Session loop-progress mutation helpers.
//!
//! Responsibilities:
//! - Increment persisted loop progress without exposing persistence details to callers.
//!
//! Not handled here:
//! - Session validation.
//! - Recovery prompting.
//!
//! Invariants/assumptions:
//! - Missing session files are a no-op.
//! - Progress updates reuse the same persistence path as session recovery.
use Path;
use Result;
use ;
/// Increment the session's tasks_completed_in_loop counter and persist.