Publish the npm tarball by explicit file path

npm parses a relative path that contains a slash but no ./ prefix as
a GitHub owner/repo shorthand, so the first javascript release run
executed `git ls-remote ssh://git@github.com/dist/payjoin-0.2.0.tgz`
and failed on SSH auth instead of publishing the local tarball. The
./ prefix disambiguates the argument as a file path; reproduced and
verified against npm 11.6.2 with `npm publish --dry-run`.

Author: spacebear21

.github/workflows/javascript.yml

@@ -152,7 +152,10 @@ jobs:
           subject-path: ${{ steps.locate.outputs.tarball }}
 
       - name: Publish to npmjs.com
-        run: npm publish "${{ steps.locate.outputs.tarball }}"
+        # The ./ prefix is load-bearing: npm parses a relative path with a
+        # slash and no ./ prefix as a GitHub owner/repo shorthand and tries
+        # to fetch it over git instead of reading the local tarball.
+        run: npm publish "./${{ steps.locate.outputs.tarball }}"
 
   github-release:
     name: "Attach tarball + SHA256SUMS to the GitHub release"