Add a "PII — maskeren & parsen" section to /concepts demonstrating the WP-40 pieces with FP + atomic design, framed for AVG art. 9 / data-minimisation: a live <app-masked-value> atom (masked BSN that reveals on click; real reveal is step-up + audited in behandel-scherm) and a live parseBsn elfproef parse. Both show the real linked source via the WP-39 snippet mechanism (new showcase regions in bsn.ts + pii.ts, registered in gen-snippets.mjs). Delivers WP-42's showcase demo; the persisted-audit half stays pending WP-41. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>