- Install pdfjs-dist v5 and add optimizeDeps pre-bundle config
- New PdfViewer.svelte component: renders each page on a <canvas> with
correct device-pixel-ratio scaling, overlays a text layer (enables
text selection; foundation for annotations in #40), prev/next
navigation, zoom controls, and lazy page rendering (only current ±1
pre-fetched — avoids freezing on multi-page documents)
- Replace the <iframe> in documents/[id]/+page.svelte with PdfViewer;
image attachments continue to use <img>; detection now uses
doc.contentType instead of filename extension
- Unit tests for navigation controls and page counter (pdfjs mocked)
- E2E tests: PDF renders as canvas (not iframe), nav controls visible,
image fallback stays as <img>; minimal.pdf fixture for upload tests
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>