Squashed onto main, with the maintainer's asks applied:
- Photoshop's blend menus (layers, brush, pencil, gradient, layer style) stay as they are;
the Layers panel and Blending Options list a Paint.NET mode only for a layer that uses one.
- The six Paint.NET mode labels are translated in every catalog, and the blend-mode i18n test
iterates layer_modes().
- pdn::pixels rejects truncated uncompressed (version 1) data before allocating its buffer.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
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