Add Arch Linux official WSL image to the distribution manifest

[Robin Candau (Antiz96)]

As discussed in #12551, we (Arch Linux) now provide an official WSL image. This commit adds it to the Microsoft WSL's official distribution manifest, allowing users to pull and install it in an automated way (wsl --install archlinux).

Closes #12551

[Robin Candau (Antiz96)]

As said in #12551 (comment), the future monthly pull requests opening should be automated on our side.

I remain available if needed! :)

[Robin Candau (Antiz96)]

Our image is compressed with zstd (.tar.zst) which the distributions/validate-modern.py script doesn't seem to support currently.
If that's of interest, I can look at adding support for it to the script :)

[Blue (OneBlue)]

Thank you for doing this Robin Candau (@Antiz96).

Unfortunately WSL indeed doesn't officially support zstd compression. The version of bsdtar we use in WSL2 happens to support it, but WSL1 doesn't. For instance, if I try to install Archlinux in WSL1 mode I get:

λ wsl --install --from-file  archlinux-2025.04.01.123847.wsl --version 1
Installing: archlinux-2025.04.01.123847.wsl
bsdtar: Error opening archive: Unrecognized archive format ]
Importing the distribution failed.
Error code: Wsl/Service/RegisterDistro/WSL_E_IMPORT_FAILED

We usually recommend distributions to compress with gz, or xz. Would that be an option for Archlinux ?

[Robin Candau (Antiz96)]

Unfortunately WSL indeed doesn't officially support zstd compression.

Oh, I wasn't aware of this. Sorry 🤭

We usually recommend distributions to compress with gz, or xz. Would that be an option for Archlinux ?

Yes, that should be doable :)
I will adapt our build system accordingly and update this PR with an image compressed with either gz or xz shortly.

[Robin Candau (Antiz96)]

PR updated with an image compressed with xz :)

[Blue (OneBlue)]

LGTM !

[Craig Loewen (craigloewen-msft)]

LGTM too! :) Thanks for the awesome contribution!!