Create ZIM file for Kiwix in build process

[ethantrithon]

It would be neat to have a ZIM file (for use in Kiwix and other similar readers) for offline access to the documentation.
A thread on discord showed that it's possible to create it locally or in this case on the build server.

The command that creates this is as follows:

zimwriterfs \
        -w index.html \
        -I zimfile-illust.png \
        -l eng \
        -n "gbdev-pandocs" \
        -t "Game Boy™ Pan Docs" \
        -d "Community-created Game Boy™ development documentation" \
        -c "GBDev Community" \
        -p "GBDev Community" \
        -a "gameboy;game boy;nintendo;development;assembly;programming;dev;asm;gbdev;pandocs" \
        -e "https://gbdev.io/pandocs/" \
        BUILD-OUTPUT-DIR/ \
        pandocs.zim

The flags here are

• w: default page
• I: icon for the zim file (this can be created on the fly with imagemagick or just added to git)
• l: language code (3 letters)
• n: name of the file (used interally for stuff)
• t: user-facing title
• d: description
• c: creator (of the content)
• p: publisher (creator of the zim file)
• a: arbitrary tags
• e: original source URL

Would be cool if we can get this step added to the build process so the ZIM file is created automatically, and it could be added to the github binaries list, or of course linked elsewhere too, perhaps even from within pandocs itself.

[ISSOtm]

The good: we only need to apt install zim-tools to get zimwriterfs (though -a is not supported in Ubuntu 24.04's 3.2.0, but it's fine as we should be able to use long options (right?)

We can also generate the illustration from the favicon automatically, which feels appropriate IMO: magick favicon.png -scale 48x48 zimfile-illust.png. Is there any documentation on guidelines for ZIM illustrations?

The pending questions:

• How should we publish the resulting files? Do we want them...
  • Built with every commit? Periodically?
  • Archived? Only the last version kept available?
• How should we link to them from the online docs? Just having this available on GitHub would pretty much zero its usage, we need to figure out discovery.
• Can we keep a single source of truth for the tags and source URL? (Probably not, I've checked and I don't believe they're anywhere in the repo. Though this also raises that we don't have a keywords meta tag..!)

[ethantrithon]

Long options should do the same thing as short options so yeah that oughtta work?
There isn't really "guidelines", but they require it to be 48x48 in size.

I would vote:

• Built every commit
• Just keep the last version, if history is needed people can see the markdown on github, or make their own copies as necessary
• Linking to the file from pandocs might be cool, and perhaps for a while "advertise it" in the discord as well?

As for the source URL and the tags...... yeah we should get that sorted :D but those are optional arguments for zimwriterfs, we can get started without those in and add them later.