Publish v0.1.0 image; fix publish namespace and docker sample workflows

- publish-image.sh: add REGISTRY_NAMESPACE for Gitea Container Registry path
- sample workflows: run docker login/build/push on host label (bundled docker
  CLI + mounted socket); fix doubled image path in build/push sample
- docs: record v0.1.0 publish and remaining secret-gated push validation

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/publish-image.sh

@@ -4,6 +4,9 @@ set -euo pipefail
 
 IMAGE_NAME="${IMAGE_NAME:-custom-gitea-runner}"
 REGISTRY="${REGISTRY:-registry.alwisp.com}"
+# Gitea Container Registry namespaces images under an owner (user/org), e.g.
+# registry.alwisp.com/<owner>/<image>. Set REGISTRY_NAMESPACE to that owner.
+REGISTRY_NAMESPACE="${REGISTRY_NAMESPACE:-jason}"
 VERSION="${VERSION:-}"
 
 if [ -z "$VERSION" ]; then
@@ -11,9 +14,16 @@ if [ -z "$VERSION" ]; then
     exit 1
 fi
 
+# Build the remote repository path, including the namespace when one is set.
+if [ -n "${REGISTRY_NAMESPACE}" ]; then
+    REMOTE_REPO="${REGISTRY}/${REGISTRY_NAMESPACE}/${IMAGE_NAME}"
+else
+    REMOTE_REPO="${REGISTRY}/${IMAGE_NAME}"
+fi
+
 LOCAL_TAG="${IMAGE_NAME}:${VERSION}"
-REMOTE_TAG="${REGISTRY}/${IMAGE_NAME}:${VERSION}"
-REMOTE_LATEST="${REGISTRY}/${IMAGE_NAME}:latest"
+REMOTE_TAG="${REMOTE_REPO}:${VERSION}"
+REMOTE_LATEST="${REMOTE_REPO}:latest"
 
 echo "Tagging ${LOCAL_TAG} as ${REMOTE_TAG} ..."
 docker tag "${LOCAL_TAG}" "${REMOTE_TAG}"