The logo, signature, stamp and cancelled watermark were placed with ExcelJS
two-cell (tl/br) anchors, which stretch each image to fill a cell range —
distorting them and making the watermark text small/squished. The PDF looked
fine because CSS sizes by aspect.
- New lib/image-size.ts: getImageSize (PNG/JPEG/WebP header parse) + scaleToBox.
- Export route now places each image with a oneCell `tl` + pixel `ext`,
aspect preserved and matched to the PDF sizes (logo ≤96×52, signature ≤165×44,
stamp ≤80×66, watermark ≤880×720).
- Watermark regenerated as a landscape canvas with the text filling it, so it
spans the page like the PDF instead of sitting small in the centre.
- Unit test for getImageSize + scaleToBox.
Verified structurally: generated XLSX uses oneCellAnchors with fixed pixel
ext sizes (49×52 / 45×44 / 67×66 / 880×629), not stretched cell ranges.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
