Run Sized Linux checks on the existing Gitea runner

SHIPMENT.md

@@ -23,9 +23,30 @@ in a separate PR so reviewers can distinguish behaviour changes from packaging.
    use the release steps below when explicitly authorized. Reconcile legacy
    GitLab download/package links before announcing a Gitea release.
 
-Use the same Linux check script in Gitea CI when a Docker-capable runner is
-configured. The current branch provides the local entry point; it does not
-configure a runner or enable automatic publishing.
+### Gitea Linux CI
+
+`.gitea/workflows/linux.yml` uses the existing `himesan-node24` label on
+cliff-mads, overriding the job image with the pinned Sized Rust runtime.
+The runner itself launches the two tmpfs mounts. Jobs have no Docker socket
+and run `scripts/check-linux-container.sh` as UID 65532, using the checked-out
+workspace as `SIZED_TEST_SOURCE`. Its tests, strict Clippy, formatting and
+optimized-binary smoke test are the same as the local Docker workflow.
+
+The runtime contains Rust 1.88.0, rustfmt/Clippy and Node for the pinned checkout
+action. On cliff-mads, rebuild it explicitly with:
+
+```bash
+ssh cliff-mads 'docker build --platform linux/amd64 --tag local/gamertan-ci:sized-rust188 -' < scripts/gitea-linux.Dockerfile
+ssh cliff-mads 'docker image inspect local/gamertan-ci:sized-rust188 --format "{{.Id}}"'
+```
+
+Review and update the workflow's image ID after an intentional rebuild; images
+stay local to the runner host. No runner labels, global isolation settings or
+publishing credentials are required. Repository Actions must be enabled.
+Only owner-triggered, same-repository code runs on this shared homelab runner.
+Source changes on main/the review branch and PRs to main trigger checks;
+documentation-only pushes skip builds. Manual dispatch is also available.
+This workflow does not publish or tag releases.
 
 ## 1. Versioning and Tagging