Story 2.2: migrate overlay dependencies to python 3.11 + v1.5 compiled locks
requested to merge bmad-loop/20260812-135642-0fc1/2-2-migrate-dependencies-python-3-11 into feat/opea-1.5-upgrade/prd
Trace MR created by bmad-loop story-track. (Re-point of !286 (closed) — GitLab API does not support source_branch change; new branch carries the 2-2 re-drive + build fixes.)