git-remote-rad: Work better with `jj` — heartwood

This patch was made entirely from within a jj repository that is not co-located in a git repository. I would not recommend doing that though: It still requires a lot of manual configuration and hand-holding.

The necessary changes were:

git-remote-rad: Allow pushing from bare repositories

Bare git repositories are meant to fetch into/push from and fetching works, but pushing from a bare repo into radicle-storage was prohibited.

This is a problem for me as I want to use jj, which uses a bare git repository in the back (when not co-located into a “normal” git repository).

git-remote-rad: Allow pushing commit SHAs into refs/patches

This makes scripting so much simpler than having to change HEAD or create a branch first.

     Ok(())
 }
 fn commit_from_string<'repo>(
     working: &'repo git::raw::Repository,
     src: &'_ str,
 ) -> Result<git::raw::Commit<'repo>, Error> {
     if let Ok(oid) = git::raw::Oid::from_str(src) {
         if let Ok(object) = working.find_commit(oid) {
             return Ok(object);
         }
     }
     let reference = working.find_reference(src)?;
     let commit = reference.peel_to_commit()?;
     Ok(commit)
 }
 /// Open a new patch.
 fn patch_open<G>(
     src: &git::RefStr,

 where
     G: crypto::signature::Signer<crypto::Signature>,
 {
     let reference = working.find_reference(src.as_str())?;
     let commit = reference.peel_to_commit()?;
     let commit = commit_from_string(working, src.as_str())?;
     let dst = git::refs::storage::staging::patch(nid, commit.id());
     // Before creating the patch, we must push the associated git objects to storage.

     // Nb. The *force* indicator (`+`) is processed by Git tooling before we even reach this code.
     // This happens during the `list for-push` phase.
     let refspec = git::Refspec { src, dst, force };
     let repo = working.workdir().ok_or(Error::BareRepository {
         path: working.path().to_path_buf(),
     })?;
     let repo = working.workdir().unwrap_or_else(|| working.path());
     radicle::git::run::<_, _, &str, &str>(
         repo,