cottongin
61fb11cae3
feat: Add PNG cover image support for EPUB books (#827)
Cherry-pick upstream PR #827 with conflict resolution for mod/master:
- Add PngToBmpConverter library for PNG cover → BMP conversion
- Add PNG thumbnail generation in generateThumbBmp()
- Fix generateCoverBmp() PNG block to use effectiveCoverImageHref
(consistent with mod's fallback cover candidate probing)
- Add .png to getCoverCandidates() extensions
- Use LOG_ERR macro in ImageToFramebufferDecoder (mod standard)
- Upstream image converter refinements (ImageBlock, PixelCache,
JpegToFramebufferConverter, PngToFramebufferConverter)
Co-authored-by: Cursor <cursoragent@cursor.com>