[JFWooten4]

Summary

• Adds Browse document images to the PDF viewer’s Tools menu.
• Finds embedded raster images on demand using PDF.js image coordinates, skipping full-page scan backgrounds and tiny decorative images.
• Displays a natural-color image viewer with previous/next arrows, keyboard navigation, page references, and a thumbnail strip.
• Includes a Go to page action to navigate back to the original document.
• Scans progressively and yields to the browser so large PDFs can begin showing results before the scan completes; pauses scanning when closed.

Validation

• Added unit coverage for image bounds, rotated/clipped corners, scan-background exclusions, and thumbnail crop coordinates (tests/image-gallery.test.mjs).
• GitHub Actions Build extension passed on the latest branch commit, including npm tests, the extension build, and the packaging check. Visual browser verification is still recommended.

Notes

• The gallery works with raster images recognized by PDF.js; vector-only diagrams are not separate embedded image objects.
• Gallery rendering uses cropped PDF canvases rather than exporting the original compressed image bytes.