Preserve Hugging Face metadata when checkpointing - #647

these 2 derivations will be built:
  /nix/store/rzz61xckkx3kxr93kdqish8kz15hj1bn-treefmt.drv
  /nix/store/njasqqjndgsahf4n6ylb801rbig6sg1w-treefmt-check.drv
these 21 paths will be fetched (238.6 MiB download, 1.1 GiB unpacked):
  /nix/store/9db7xb1axdgqp4lakdxbp27yh7kfvm0b-cargo-1.91.1
  /nix/store/95a688lk14i0y5y70fwh9qhjd84490yd-clang-tools-21.1.7
  /nix/store/2f0m15fl4wggza192zd2965ybv7ip6qc-git-lfs-3.7.1
  /nix/store/rjx80xk7ly0i4d6sflilvphpx9drqdgd-just-1.46.0
  /nix/store/yx338k689yp9hpnl6h5y22f7vbmi5pky-nixfmt-1.2.0
  /nix/store/8sa75mbvbn3kxicggyyjggmkigvzddks-prettier-3.6.2
  /nix/store/qwq4q8pmxl5wsbgvmdvh54bc21hbdmhd-prettierrc.json
  /nix/store/vck0nmayfp8i4fv3faccs0h176qkczcl-python3.13-beautysh-6.4.2
  /nix/store/pxx5sw14dylyz58r5adyrk6hqkraxbn8-python3.13-black-25.1.0
  /nix/store/j7qlfl0lw3n1ykv5qa7rz6c1mxiyplcs-python3.13-click-8.3.1
  /nix/store/wpg4wf9qrfzl622spndcfvj0j7mlb018-python3.13-editorconfig-0.17.1
  /nix/store/218ic1802dyzkny8i7il2cfpz10qshfk-python3.13-flit-core-3.12.0
  /nix/store/y54jfgcvsa6frcy4j67lvyc957papnm9-python3.13-mypy-extensions-1.1.0
  /nix/store/0sysb5d290jn8c4w7jkllm29sng1pnq8-python3.13-platformdirs-4.5.0
  /nix/store/hx9wh212gnd3s9dgbhm1ipwx3byhlf25-python3.13-types-colorama-0.4.15.20250801
  /nix/store/k90kpbsf6amcvbyb43yxlfkzycpxbj8y-rustc-1.91.1
  /nix/store/lvdr3nws8gs2qcgm3rnwvjprcx55kx7l-rustc-wrapper-1.91.1
  /nix/store/i1zl6150nc77vryj6n9razki0l5bzxv5-rustfmt-1.91.1
  /nix/store/4mqmhfj7swjdxd1jxnwirr3fi05gwrf3-taplo-0.10.0
  /nix/store/1pdwlp9d1rrm3xp4s5rhhk7mkmx9cmv2-treefmt-2.4.0
  /nix/store/f3byyx2a0b2asn20df7dmnr5xjy1wind-treefmt.toml
treefmt-check> treefmt v2.4.0traversed 780 files
treefmt-check> emitted 686 files for processing
treefmt-check> formatted 686 files (1 changed) in 5.095s
treefmt-check>  M shared/data-provider/src/hub.rs
treefmt-check> diff --git a/shared/data-provider/src/hub.rs b/shared/data-provider/src/hub.rs
treefmt-check> index 902c5c7..6f8b836 100644
treefmt-check> --- a/shared/data-provider/src/hub.rs
treefmt-check> +++ b/shared/data-provider/src/hub.rs
treefmt-check> @@ -277,7 +277,7 @@ pub async fn upload_to_hub(
treefmt-check>  
treefmt-check>  #[cfg(test)]
treefmt-check>  mod tests {
treefmt-check> -    use super::{check_extensions, MODEL_EXTENSIONS};
treefmt-check> +    use super::{MODEL_EXTENSIONS, check_extensions};
treefmt-check>      use hf_hub::api::Siblings;
treefmt-check>  
treefmt-check>      #[test]
error: build of '/nix/store/njasqqjndgsahf4n6ylb801rbig6sg1w-treefmt-check.drv' on 'ssh-ng://nix-ssh@garnix7' failed: Cannot build '/nix/store/njasqqjndgsahf4n6ylb801rbig6sg1w-treefmt-check.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/krd7b95q1nx41679ccbbr6ghdxcgzlcr-treefmt-check
       Last 17 log lines:
       > treefmt v2.4.0traversed 780 files
       > emitted 686 files for processing
       > formatted 686 files (1 changed) in 5.095s
       >  M shared/data-provider/src/hub.rs
       > diff --git a/shared/data-provider/src/hub.rs b/shared/data-provider/src/hub.rs
       > index 902c5c7..6f8b836 100644
       > --- a/shared/data-provider/src/hub.rs
       > +++ b/shared/data-provider/src/hub.rs
       > @@ -277,7 +277,7 @@ pub async fn upload_to_hub(
       >  
       >  #[cfg(test)]
       >  mod tests {
       > -    use super::{check_extensions, MODEL_EXTENSIONS};
       > +    use super::{MODEL_EXTENSIONS, check_extensions};
       >      use hf_hub::api::Siblings;
       >  
       >      #[test]
       For full logs, run:
         nix log /nix/store/njasqqjndgsahf4n6ylb801rbig6sg1w-treefmt-check.drv
error: Cannot build '/nix/store/njasqqjndgsahf4n6ylb801rbig6sg1w-treefmt-check.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/krd7b95q1nx41679ccbbr6ghdxcgzlcr-treefmt-check