Harmonize archived-model ACS predictors at pool assembly (end state for the release-side join)

End-state decision recorded from the ACS-predictor work (weeksgate report, "Owner rulings required"; interim fix = release-side join from the sha-pinned ACS zips, PR to follow from branch acs-predictor-release-join): the archived release-stage donor models' CPS-named predictors (PEDIS*, PRDTRACE, PRDTHSP, PEIOOCC, POCCU2, SPM_TENMORTSTATUS) should ultimately be harmonized at POOL ASSEMBLY from native ACS variables (DEAR/DEYE/DREM/DPHY/DDRS/DOUT, RAC1P, HISP, OCCP, TEN), so the pool itself carries complete predictors and the release-side join can be deleted. Assembly-stage change invalidates the checkpoint chain from assembly, so this rides the next cold pool rebuild (the parsimony candidate's build is the natural vehicle) rather than forcing a ~15h rebuild of the current candidate.

Start by locating the pool assembly entry point and the release-side join described in the issue, then inspect how the native ACS variables and archived donor-model predictors are handled. The change is complete when the pool carries the listed harmonized predictors and the release-side join can be removed; validate it through the next cold pool rebuild rather than rebuilding the current candidate.