[FEAT] New mod - calibre-kfxgen #1171

Is this a new feature request?

• I have searched the existing issues

Name of mod

calibre-kfxgen

Wanted change

Please create a calibre-kfxgen branch from template so I can submit a PR adding native KFX conversion to the LinuxServer.io Calibre image.

Reason for change

jloutsch/kfxgen generates KFX without Wine or Kindle Previewer. This lets users convert books through the existing Calibre browser desktop without another image or service.

The mod installs the bundled plugin as abc into /config/.config/calibre before services start. It preserves plugin preferences and does not disable other plugins; users must disable KFX Output if installed because it otherwise takes priority.

Proposed code change

Prepared on my fork's calibre-kfxgen branch, based on your template branch:

• Single-layer scratch mod with an s6 v3 init script.
• Pinned plugin ZIP with SHA-256 verification and bundled GPLv3 source/license.
• Your template build workflow, with BASEIMAGE=calibre, MODNAME=kfxgen, and the official repository/registry settings unchanged.
• An integration smoke test for startup, PUID/PGID ownership, native conversion, and disabled-plugin preference preservation across restart.

The port passed its integration smoke test on an amd64 Linux Docker host. The standalone implementation also has passing CI and published amd64/arm64 images. Arm64 runtime and Kindle rendering have not been validated. Formatting, particularly Arabic/RTL, can differ from Previewer.

I can adapt version-update automation to your preferred process before submitting the PR.