Rename rollout tracker: surfaces still on populace names (frozen v1 + external consumers)

Tracks every surface still carrying the old names after the 2026-08-07 rename execution (repos, site, dashboard, chronicle all done — see microcosm#638 for the namespace PR).

Deliberately frozen at v1 (migrate only with versioned tooling):

• HF dataset repo ids policyengine/populace-us[-staging], populace-uk-private, populace-be-* (+ artifact filenames inside them) — needs HF move/redirect verification + new certified release
• Release/build id prefixes (populace-us-2024-*, …) — flip prefix at the next certified build
• Artifact filename templates (base_populace_us_*, populace_uk_*_rowwise*, populace_be_{year}.h5)
• POPULACE_* env vars (CI secrets + keychain mappings) — rename with dual-read fallback
• Trace namespace for OLD records (new records already use microcosm.institute/trace)

External consumers to update (redirects cover them meanwhile):

• policyengine.py — populace-data dep/manifest naming (issue filed there)
• policyengine-us — docstring issue links (populace#244/#249 style) + DEFAULT_DATASET comment context
• policyengine-skills, policybench, policyengine-scorecard prose
• Papers repos (sparsity/l0, imputation, transfer, calibration) — cite microcosm.institute going forward; populace.dev 301s path-preservingly
• microcosm-dynamics: GitHub Pages URL changed with the repo rename (no Pages redirect); PDF content still says Populace (regen after microcosm-dynamics rename PR)
• societalcomputation.org constellation page wordmark link → https://microcosm.institute (Thesis session repointing)
• og-image.png regen (chipped)

Start with the checklist in this issue and microcosm#638, then inspect the frozen dataset, build-prefix, artifact-template, and POPULACE_* naming surfaces. Review the listed external consumers, including policyengine.py, policyengine-us, microcosm-dynamics, and societalcomputation.org. Done means each remaining old name is migrated with the required versioned tooling or explicitly covered by redirects and regeneration work.