The L40S smoke template uses CARGO_TARGET_DIR=/cargo-target on a
persistent PVC, so every smoke probe builds incrementally on top of
artefacts left by prior probes. File deletions (e.g., regime_conditional.rs
in ff00af68a) can leave dangling rmeta/object references that perturb
downstream codegen between bisect runs — making the bisect result
contingent on which order probes were submitted in, not on the source.
Adds an optional `clean-cache` parameter (default `false`) which runs
`cargo clean -p ml -p ml-dqn --release` before the compile step. Other
crate artefacts (ml-core, ml-supervised, etc.) stay cached so the wipe
is bounded — fresh ml/ml-dqn compile in ~3-5 min vs ~30+ min full clean.
Use case: re-running a52d99613 + ff00af68a with `--clean-cache` to
verify the bisect under controlled build conditions. If the
broken/clean status flips with clean cache, the regression is
build-state-dependent rather than source-line; if it reproduces, the
source regression is real and bisect is definitive.
scripts/argo-smoke.sh exposes `--clean-cache` flag passing through
to the workflow parameter.