npm upgraded pdfjs-dist from 5.4.530 to 5.7.284 (^semver range) but the
manually copied worker file in public/ was left at 5.4.530, causing an
API/Worker version mismatch error at runtime. Copy matching worker from
node_modules/pdfjs-dist/build/.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>