Module loop_dispatch 

Shellout dispatcher that wraps the bash driver-lib contract.

Design: the shellout seam (grilled decision 8)

The Rust Dispatcher trait exists so a future daemon/PTY implementation can be wired in as a drop-in replacement without touching the loop runtime or the TargetQueue. This file implements the bash-shellout side only: it sources driver-<name>.sh and calls driver_invoke, delegating all session logic to the bash lib. The Rust side NEVER reimplements driver behavior; it only manages process lifecycle, env passthrough, and exit-code collection.

The seam is stable once the trait is locked (Task 1.1). A future PTY dispatcher can implement Dispatcher + Session and be swapped in by the CLI flag --dispatcher pty without changing any other code.

Binary resolution (preflight)

Mirrors scripts/run-target-loop.sh:144-150. The Rust side validates the driver whitelist and binary availability before any dispatch, so a missing binary fails loudly at startup rather than inside iteration N.

Structs

ShelloutDispatcher

Dispatcher that sources a driver lib and calls driver_invoke in bash.

ShelloutSession

A live session wrapping a bash driver_invoke child process.

Functions

driver_default_max

Query driver_default_max() from the driver lib via a single bash shellout.

preflight

Validate the driver name and confirm the driver lib file exists, the driver binary is on PATH, and the lib defines driver_invoke.

resolve_driver_binary

Resolve the binary name for a given driver name.

which_binary

Walk $PATH to find a binary. Returns Some(path) on success. Does not use an external crate; pure std.