fix(deploy): use single-line commit message to avoid expression truncation

Gitea Actions expression evaluator truncates multiline strings in
run blocks at blank lines. Using a simple single-line commit message.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitea/workflows/deploy-k8s.yaml

@@ -72,12 +72,7 @@ jobs:
           if git diff --staged --quiet; then
             echo "No image tag changes to commit"
           else
-            COMMIT_MSG="deploy: ${{ inputs.service-name }} ${IMAGE_TAG}"
-            COMMIT_MSG="${COMMIT_MSG}
-
-Source: ${SHA}
-Run: ${RUN_URL}"
-            git commit -m "${COMMIT_MSG}"
+            git commit -m "deploy: ${{ inputs.service-name }} ${IMAGE_TAG}"
             git push origin main
             echo "Cluster repo updated — ArgoCD will sync within ~3 min"
           fi