UK compute campaign, run 1: execute the mode-1 counterpart pipeline on the certified bundle

The mode-1 pipeline (#51, approved) has never executed — its own docstring says so. This issue is the first managed run and the gap-closure loop that follows.

Steps

• On the managed machine: simlock -- .venv-pe/bin/python pipeline/compute_uk_counterparts.py 2025 against the certified populace-uk bundle (populace-uk-2023-dd68c73-…, the #56-verified world) at pinned policyengine/pe-uk versions.
• Publish the resolution report from pe_uk_meta.json: which CANDIDATES names resolved, which concepts landed pe_gap, whether pe.uk.managed_microsimulation() is the real accessor spelling, which would_claim_* overrides applied and read back on, and the per-benefit fullpart movement table.
• Close the gaps the run exposes: CANDIDATES renames (one-line fixes by design), band-flag concepts (pays_basic/higher/additional_rate are name-candidates), the benunit/household country anchors, the SP-age anchor for housing_benefit_pensioners.
• Run 2 with gaps closed; ingest pe_uk_metrics.json into the DB against the #48 external rows (rates derived downstream, per the contract) and surface in the app's UK view.
• Record engine pins + bundle id per run for #65's UK release map.

Success = every dwp_takeup / hbai / uk_hmrc / obr / ukmod external family has either a joined PE counterpart or a labelled pe_gap on the page. Closes #40 when done.