Adds a View button (eye icon) on each evidence card for previewable file
types. Opens a full-screen modal:
- Images (png/jpg/gif/webp/svg/…): rendered directly via <img> tag
- JSON: fetched authenticated, pretty-printed in green mono
- Text/log/md/csv/xml/yaml/…: fetched authenticated, shown in <pre>
Non-previewable files only show the Download button as before.
Modal closes on Escape or backdrop click.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
