visibility-audit: codebook, audit logs and code for an audit of identifier schemas and record linkage in US device surveillance

Codebook and blank judgment templates (fixed 2 September 2026, before any confirmatory judgment), three codebook addenda (3 September 2026), the recorded judgments with a documentary audit log of verbatim quotations, field inventories, record-linkage outputs (MDR master-file scan, DEVICE-file join, AccessGUDID results of 2 September 2026) and analysis code for an audit of whether US FDA device surveillance data sources can retrieve adverse events across products that share an upstream component such as a foundation model. The final recorded judgments are in results/final_2026-09-26/. Documentation and data are licensed under CC BY 4.0; code is licensed under the MIT License. Raw FDA files are not redistributed; their download locations and SHA-256 hashes are in data/MANIFEST.md.