feat(docker): Add KDE kimageformats for AVIF, JXL and additional image formats

[nickv2002]

Description

Adds KDE kimageformats support to the Docker image, enabling AVIF and JXL image format support in YACReaderLibraryServer, along with 20+ additional image formats (ani, hdr, pcx, psd, qoi, xcf, etc.).

Changes

• Reorganize Dockerfile into multi-stage build (base, sevenzip-builder, kimageformats-builder, yacreader-builder, runtime)
• Add kimageformats-builder stage for building KDE kimageformats 6.0.0 with ECM 6.0.0
• Copy kimageformats plugins to both builder and runtime stages
• Add runtime dependencies: libavif16 and libjxl0.7
• Fix COPY path for root.tar.gz: COPY docker/root.tar.gz / (relative to build context root)

Supported Formats

✅ New formats with this PR:

• AVIF / AVIFS (libavif)
• JXL (libjxl)

✅ Bonus formats included:

• ani, bw, eps, hdr, ico, pcx, pic, psd, qoi, ras, rgb, tga, xcf (and more)

❌ Not supported in kimageformats 6.0.0:

• HEIC/HEIF (requires kimageformats 6.1+, not available in Ubuntu 24.04 Noble)

Testing

• ✅ Docker image builds successfully
• ✅ AVIF and JXL formats recognized by Qt
• ✅ Comics with AVIF/JXL covers properly scanned
• ✅ 3 test comics processed successfully: avif.cbz, jxl.cbz, test_combined.cbz
• ✅ HEIC/HEIF files gracefully skipped (not supported)

Notes

• Build from source required: Both ECM 6.0.0 and kimageformats 6.0.0 must be built from KDE source because Ubuntu Noble only provides older KF5 framework versions (ECM 5.115.0). KF6 framework is required for AVIF/JXL support.
• Path fix note: The COPY docker/root.tar.gz / uses the full path because docker build context is the repository root, and root.tar.gz is located in the docker/ subdirectory.
• Dockerfile.aarch64 is NOT modified; ARM support can be addressed in a follow-up PR if this is approved

Comparison with PR #499

This approach uses KDE official kimageformats library instead of custom Qt plugin builds:

• ✅ Smaller diff, easier to maintain
• ✅ More formats supported (30+ vs 4)
• ✅ Official upstream library
• ❌ HEIC/HEIF not supported (would require newer kimageformats version)

[luisangelsm]

@nickv2002 thanks! did you try to install kimageformat-plugins instead of building them? like adding kimageformat-plugins to the list of packages installed.

[nickv2002]

@nickv2002 thanks! did you try to install kimageformat-plugins instead of building them? like adding kimageformat-plugins to the list of packages installed.

I tried the versions from apt but:

Build from source required: Both ECM 6.0.0 and kimageformats 6.0.0 must be built from KDE source because Ubuntu Noble only provides older KF5 framework versions (ECM 5.115.0). KF6 framework is required for AVIF/JXL support.

Could rebase the image on a different & newer distro but that would introduce other changes.

[luisangelsm]

Could rebase the image on a different & newer distro but that would introduce other changes.

What changes? Any downsides?

[nickv2002]

Could rebase the image on a different & newer distro but that would introduce other changes.

What changes? Any downsides?

That would require significantly reworking because the base docker image to a more leading edge version of alpine/fedora/arch. It also doesn't seem in keeping with your previously expressed interest in minimizing maintenance work and support burdens.

[selmf]

I think we could use a newer non-LTS Ubuntu base image.

There's also another option I have used before - the KDE Neon Distro is based on Ubuntu LTS (noble) and should have the latest Qt and kimageformats. We could add the apt/ppas and just use those.