Add audit: stats v4.0 population-regression (map vs stats population parity)

[badjoke-lab]

Motivation

• Produce an evidence-based audit that determines which commit/PR changed the population (母集合) behavior between /api/places and /api/stats without modifying code.
• Verify whether /api/stats aggregations total/breakdown/rankings/chains/matrix all reference the same WHERE/source.
• Produce a standalone report docs/audits/stats-v4.0-population-regression.audit.md that records findings and the precise commits examined.

Description

• Added docs/audits/stats-v4.0-population-regression.audit.md that documents the investigation, observed commits, and concrete code locations; no application code was changed.
• Traced the relevant changes to two observable commits: 366eb16... (PR [Stats v4.0 Parity PR-1] Align stats population with map-displayable places #253) which introduced lib/stats/mapPopulation.ts and unified the map-displayable WHERE via getMapDisplayableWhereClauses / isMapDisplayablePlace, and 2f663dc... (PR Stats v4.0 parity PR-2: align verification breakdown counts and ship donut UI #254) which altered verification aggregation logic (LATERAL/subquery, normalization) and added the breakdown field while retaining the unified WHERE usage.
• Confirmed that v4 DB-path aggregations use a shared WITH filtered_places AS (...) CTE built from getMapDisplayableWhereClauses, and identified remaining divergence vectors that can cause population mismatches: verification interpretation differences (Map uses LEFT JOIN verifications, Stats uses LEFT JOIN LATERAL with priority), and string-normalization differences for accepted/country/city/category; also documented stats_cache and JSON-fallback as separate sources.

Testing

• No automated tests were run for this change (this PR only adds an audit document and performs code inspection).

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Codex Task

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Project	Deployment	Actions	Updated (UTC)
cryptopaymap-v2	Ready	Preview, Comment	Feb 24, 2026 3:59am