Adds use-multi-head-policy workflow parameter (default "0") wired
into the container env block as FOXHUNT_USE_MULTI_HEAD_POLICY.
Adds --use-multi-head-policy flag to argo-alpha-rl.sh that passes
through to the workflow.
Enables Phase 2A-E cluster verification with the multi-head policy
mixture (commits 0b3e40150 → c8c81ab7e). Without this flag, the
cluster runs the legacy single-head path identical to pre-Phase-2A
behavior.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>