test: regenerate the coverage report and the sweep baseline, document the baseline and the runner policy

README.md

@@ -313,7 +313,8 @@ against a live Gitea 28.1.0, for the per-tool outcome.
 - Some operations depend on instance state and answer 404 or an error until it exists: the
   commit signing keys (`gitea_misc_get_signing_key`, `gitea_repo_signing_key` and their SSH
   variants) when the instance has none, user badges (Gitea cannot create badges through the
-  API), unadopted repositories, and similar. The coverage report lists them with the reason.
+  API), unadopted repositories, run artifacts, git notes and the GPG key verification, which
+  need data the instance does not have yet. The coverage report lists them with the reason.
 - Tools that depend on a runner, such as workflow runs and jobs, only return data once an
   Actions runner is registered.